{
 "temperature_formulas": "T/K = t/°C + 273.15; t/°C = (t/°F − 32)/1.8; T/K = (t/°F + 459.67)/1.8; °R = K × 9/5",
 "fuel_economy_formulas": "L/100km = 235.214583333.../mpg_US = 100×3.785411784/(1.609344×mpg); = 282.480936331.../mpg_UK",
 "units": [
  {
   "category": "length",
   "unit": "mm",
   "name": "millimeter",
   "value_in_base": "0.001",
   "base_unit": "m",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "length",
   "unit": "cm",
   "name": "centimeter",
   "value_in_base": "0.01",
   "base_unit": "m",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "length",
   "unit": "m",
   "name": "meter",
   "value_in_base": "1",
   "base_unit": "m",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "length",
   "unit": "km",
   "name": "kilometer",
   "value_in_base": "1000",
   "base_unit": "m",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "length",
   "unit": "in",
   "name": "inch",
   "value_in_base": "0.0254",
   "base_unit": "m",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "length",
   "unit": "ft",
   "name": "foot",
   "value_in_base": "0.3048",
   "base_unit": "m",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "length",
   "unit": "yd",
   "name": "yard",
   "value_in_base": "0.9144",
   "base_unit": "m",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "length",
   "unit": "mi",
   "name": "mile",
   "value_in_base": "1609.344",
   "base_unit": "m",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "length",
   "unit": "nmi",
   "name": "nautical mile",
   "value_in_base": "1852",
   "base_unit": "m",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8",
    "NIST SP 811, Appendix B footnotes"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8",
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-footnotes"
   ],
   "note": ""
  },
  {
   "category": "length",
   "unit": "mil",
   "name": "thousandth inch (mil)",
   "value_in_base": "0.0000254",
   "base_unit": "m",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "length",
   "unit": "µm",
   "name": "micrometer",
   "value_in_base": "0.000001",
   "base_unit": "m",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "mass",
   "unit": "mg",
   "name": "milligram",
   "value_in_base": "0.000001",
   "base_unit": "kg",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "mass",
   "unit": "g",
   "name": "gram",
   "value_in_base": "0.001",
   "base_unit": "kg",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "mass",
   "unit": "kg",
   "name": "kilogram",
   "value_in_base": "1",
   "base_unit": "kg",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "mass",
   "unit": "t",
   "name": "metric ton",
   "value_in_base": "1000",
   "base_unit": "kg",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8",
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8",
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "mass",
   "unit": "oz",
   "name": "ounce",
   "value_in_base": "0.028349523125",
   "base_unit": "kg",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B footnotes",
    "NIST Handbook 44 (2026), Appendix C"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-footnotes",
    "https://www.nist.gov/document/2026-nist-handbook-44-appendix-c"
   ],
   "note": "16 oz = 1 lb"
  },
  {
   "category": "mass",
   "unit": "lb",
   "name": "pound",
   "value_in_base": "0.45359237",
   "base_unit": "kg",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B footnotes",
    "NIST Handbook 44 (2026), Appendix C"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-footnotes",
    "https://www.nist.gov/document/2026-nist-handbook-44-appendix-c"
   ],
   "note": ""
  },
  {
   "category": "mass",
   "unit": "st",
   "name": "stone",
   "value_in_base": "6.35029318",
   "base_unit": "kg",
   "exact": true,
   "sources": [
    "NIST Handbook 44 (2026), Appendix C",
    "UK Weights and Measures Act 1985, Schedule 1"
   ],
   "source_urls": [
    "https://www.nist.gov/document/2026-nist-handbook-44-appendix-c",
    "https://www.legislation.gov.uk/ukpga/1985/72/schedule/1/enacted"
   ],
   "note": "stone = 14 lb (UK)"
  },
  {
   "category": "mass",
   "unit": "ton-us",
   "name": "short ton (US)",
   "value_in_base": "907.18474",
   "base_unit": "kg",
   "exact": true,
   "sources": [
    "NIST Handbook 44 (2026), Appendix C"
   ],
   "source_urls": [
    "https://www.nist.gov/document/2026-nist-handbook-44-appendix-c"
   ],
   "note": "short ton 2000 lb"
  },
  {
   "category": "mass",
   "unit": "ton-uk",
   "name": "long ton (UK)",
   "value_in_base": "1016.0469088",
   "base_unit": "kg",
   "exact": true,
   "sources": [
    "NIST Handbook 44 (2026), Appendix C",
    "UK Weights and Measures Act 1985, Schedule 1"
   ],
   "source_urls": [
    "https://www.nist.gov/document/2026-nist-handbook-44-appendix-c",
    "https://www.legislation.gov.uk/ukpga/1985/72/schedule/1/enacted"
   ],
   "note": "long ton 2240 lb"
  },
  {
   "category": "volume",
   "unit": "mL",
   "name": "milliliter",
   "value_in_base": "0.001",
   "base_unit": "L",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "volume",
   "unit": "L",
   "name": "liter",
   "value_in_base": "1",
   "base_unit": "L",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "volume",
   "unit": "m³",
   "name": "cubic meter",
   "value_in_base": "1000",
   "base_unit": "L",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "volume",
   "unit": "tsp-us",
   "name": "teaspoon (US)",
   "value_in_base": "0.00492892159375",
   "base_unit": "L",
   "exact": true,
   "sources": [
    "NIST Handbook 44 (2026), Appendix C"
   ],
   "source_urls": [
    "https://www.nist.gov/document/2026-nist-handbook-44-appendix-c"
   ],
   "note": "tsp = 1/3 tbsp"
  },
  {
   "category": "volume",
   "unit": "tbsp-us",
   "name": "tablespoon (US)",
   "value_in_base": "0.01478676478125",
   "base_unit": "L",
   "exact": true,
   "sources": [
    "NIST Handbook 44 (2026), Appendix C"
   ],
   "source_urls": [
    "https://www.nist.gov/document/2026-nist-handbook-44-appendix-c"
   ],
   "note": "tbsp = 1/2 fl oz"
  },
  {
   "category": "volume",
   "unit": "floz-us",
   "name": "fluid ounce (US)",
   "value_in_base": "0.0295735295625",
   "base_unit": "L",
   "exact": true,
   "sources": [
    "NIST Handbook 44 (2026), Appendix C"
   ],
   "source_urls": [
    "https://www.nist.gov/document/2026-nist-handbook-44-appendix-c"
   ],
   "note": "128 fl oz = 1 gal"
  },
  {
   "category": "volume",
   "unit": "cup-us",
   "name": "cup (US)",
   "value_in_base": "0.2365882365",
   "base_unit": "L",
   "exact": true,
   "sources": [
    "NIST Handbook 44 (2026), Appendix C"
   ],
   "source_urls": [
    "https://www.nist.gov/document/2026-nist-handbook-44-appendix-c"
   ],
   "note": "cup = 8 fl oz (customary; US nutrition-label cup is 240 mL)"
  },
  {
   "category": "volume",
   "unit": "pt-us",
   "name": "pint (US)",
   "value_in_base": "0.473176473",
   "base_unit": "L",
   "exact": true,
   "sources": [
    "NIST Handbook 44 (2026), Appendix C"
   ],
   "source_urls": [
    "https://www.nist.gov/document/2026-nist-handbook-44-appendix-c"
   ],
   "note": ""
  },
  {
   "category": "volume",
   "unit": "qt-us",
   "name": "quart (US)",
   "value_in_base": "0.946352946",
   "base_unit": "L",
   "exact": true,
   "sources": [
    "NIST Handbook 44 (2026), Appendix C"
   ],
   "source_urls": [
    "https://www.nist.gov/document/2026-nist-handbook-44-appendix-c"
   ],
   "note": ""
  },
  {
   "category": "volume",
   "unit": "gal-us",
   "name": "gallon (US)",
   "value_in_base": "3.785411784",
   "base_unit": "L",
   "exact": true,
   "sources": [
    "NIST Handbook 44 (2026), Appendix C"
   ],
   "source_urls": [
    "https://www.nist.gov/document/2026-nist-handbook-44-appendix-c"
   ],
   "note": "231 in³"
  },
  {
   "category": "volume",
   "unit": "gal-uk",
   "name": "gallon (UK / imperial)",
   "value_in_base": "4.54609",
   "base_unit": "L",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8",
    "UK Weights and Measures Act 1985, Schedule 1"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8",
    "https://www.legislation.gov.uk/ukpga/1985/72/schedule/1/enacted"
   ],
   "note": ""
  },
  {
   "category": "volume",
   "unit": "in³",
   "name": "cubic inch",
   "value_in_base": "0.016387064",
   "base_unit": "L",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B footnotes"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-footnotes"
   ],
   "note": ""
  },
  {
   "category": "volume",
   "unit": "ft³",
   "name": "cubic foot",
   "value_in_base": "28.316846592",
   "base_unit": "L",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "volume",
   "unit": "cm³",
   "name": "cm³",
   "value_in_base": "0.001",
   "base_unit": "L",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "pressure",
   "unit": "Pa",
   "name": "pascal",
   "value_in_base": "1",
   "base_unit": "Pa",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "pressure",
   "unit": "kPa",
   "name": "kilopascal",
   "value_in_base": "1000",
   "base_unit": "Pa",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "pressure",
   "unit": "MPa",
   "name": "megapascal",
   "value_in_base": "1000000",
   "base_unit": "Pa",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "pressure",
   "unit": "bar",
   "name": "bar",
   "value_in_base": "100000",
   "base_unit": "Pa",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "pressure",
   "unit": "mbar",
   "name": "millibar",
   "value_in_base": "100",
   "base_unit": "Pa",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "pressure",
   "unit": "psi",
   "name": "pound-force per square inch",
   "value_in_base": "6894.757293168361336722673",
   "base_unit": "Pa",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8",
    "NIST SP 811, Appendix B footnotes"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8",
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-footnotes"
   ],
   "note": ""
  },
  {
   "category": "pressure",
   "unit": "ksi",
   "name": "kilopound per square inch",
   "value_in_base": "6894757.293168361336722673",
   "base_unit": "Pa",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "pressure",
   "unit": "atm",
   "name": "standard atmosphere",
   "value_in_base": "101325",
   "base_unit": "Pa",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "pressure",
   "unit": "torr",
   "name": "torr",
   "value_in_base": "133.3223684210526315789474",
   "base_unit": "Pa",
   "exact": true,
   "sources": [
    "NIST SP 811, Chapter 5"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-chapter-5-units-outside-si"
   ],
   "note": "1 Torr = 101325/760 Pa exactly; mmHg(conv) = 133.322387415 Pa differs by 1.4e-7"
  },
  {
   "category": "pressure",
   "unit": "inHg",
   "name": "inch of mercury (conventional, 0 °C)",
   "value_in_base": "3386.388640341",
   "base_unit": "Pa",
   "exact": false,
   "sources": [
    "NIST SP 811, Appendix B.8",
    "NIST SP 811, Appendix B footnotes"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8",
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-footnotes"
   ],
   "note": "conventional inHg (13595.1 kg/m³ × gn × 1 in); B.8 3386.389. Also 32°F 3386.38, 60°F 3376.85"
  },
  {
   "category": "pressure",
   "unit": "inH2O",
   "name": "inch of water column (conventional)",
   "value_in_base": "249.08891",
   "base_unit": "Pa",
   "exact": false,
   "sources": [
    "NIST SP 811, Appendix B.8",
    "NIST SP 811, Appendix B footnotes"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8",
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-footnotes"
   ],
   "note": "conventional inH2O 249.0889 (1000 kg/m³ × gn); also 39.2°F 249.082, 60°F 248.84"
  },
  {
   "category": "pressure",
   "unit": "mmH2O",
   "name": "mm of water column (conventional)",
   "value_in_base": "9.80665",
   "base_unit": "Pa",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": "conventional mmH2O 9.80665 (bold/exact in B.8)"
  },
  {
   "category": "pressure",
   "unit": "mmHg",
   "name": "mmHg",
   "value_in_base": "133.322387415",
   "base_unit": "Pa",
   "exact": false,
   "sources": [
    "NIST SP 811, Appendix B.8",
    "NIST SP 811, Appendix B footnotes"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8",
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-footnotes"
   ],
   "note": "conventional mmHg 133.3224 (B.8)"
  },
  {
   "category": "energy",
   "unit": "J",
   "name": "joule",
   "value_in_base": "1",
   "base_unit": "J",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "energy",
   "unit": "kJ",
   "name": "kilojoule",
   "value_in_base": "1000",
   "base_unit": "J",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "energy",
   "unit": "MJ",
   "name": "megajoule",
   "value_in_base": "1000000",
   "base_unit": "J",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "energy",
   "unit": "cal",
   "name": "calorie (thermochemical)",
   "value_in_base": "4.184",
   "base_unit": "J",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8",
    "NIST SP 811, Appendix B footnotes"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8",
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-footnotes"
   ],
   "note": "thermochemical; cal_IT = 4.1868"
  },
  {
   "category": "energy",
   "unit": "kcal",
   "name": "kilocalorie (food cal)",
   "value_in_base": "4184",
   "base_unit": "J",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8",
    "NIST SP 811, Appendix B footnotes"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8",
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-footnotes"
   ],
   "note": "thermochemical kcal; kcal_IT = 4186.8"
  },
  {
   "category": "energy",
   "unit": "Wh",
   "name": "watt-hour",
   "value_in_base": "3600",
   "base_unit": "J",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "energy",
   "unit": "kWh",
   "name": "kilowatt-hour",
   "value_in_base": "3600000",
   "base_unit": "J",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "energy",
   "unit": "BTU",
   "name": "BTU (International Table)",
   "value_in_base": "1055.05585262",
   "base_unit": "J",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B footnotes"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-footnotes"
   ],
   "note": "BTU_IT; Btu_th 1054.350, mean 1055.87, 39°F 1059.67, 59°F 1054.80, 60°F 1054.68"
  },
  {
   "category": "energy",
   "unit": "eV",
   "name": "electron-volt",
   "value_in_base": "1.602176634E-19",
   "base_unit": "J",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "energy",
   "unit": "ft·lbf",
   "name": "foot-pound (force)",
   "value_in_base": "1.3558179483314004",
   "base_unit": "J",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B footnotes"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-footnotes"
   ],
   "note": ""
  },
  {
   "category": "power",
   "unit": "W",
   "name": "watt",
   "value_in_base": "1",
   "base_unit": "W",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "power",
   "unit": "kW",
   "name": "kilowatt",
   "value_in_base": "1000",
   "base_unit": "W",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "power",
   "unit": "MW",
   "name": "megawatt",
   "value_in_base": "1000000",
   "base_unit": "W",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "power",
   "unit": "hp",
   "name": "horsepower (mechanical)",
   "value_in_base": "745.69987158227022",
   "base_unit": "W",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8",
    "NIST SP 811, Appendix B footnotes"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8",
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-footnotes"
   ],
   "note": "mechanical; electric 746, boiler 9809.5, metric 735.4988, UK 745.7"
  },
  {
   "category": "power",
   "unit": "hp-m",
   "name": "metric horsepower",
   "value_in_base": "735.49875",
   "base_unit": "W",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": "exact 75 kgf·m/s definition not stated on the fetched NIST pages"
  },
  {
   "category": "power",
   "unit": "BTU/h",
   "name": "BTU per hour",
   "value_in_base": "0.2930710701722222222222222",
   "base_unit": "W",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8",
    "NIST SP 811, Appendix B footnotes"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8",
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-footnotes"
   ],
   "note": ""
  },
  {
   "category": "power",
   "unit": "ton",
   "name": "ton of refrigeration",
   "value_in_base": "3516.852842066666666666667",
   "base_unit": "W",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8",
    "NIST SP 811, Appendix B footnotes"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8",
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-footnotes"
   ],
   "note": ""
  },
  {
   "category": "power",
   "unit": "PS",
   "name": "PS",
   "value_in_base": "735.49875",
   "base_unit": "W",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": "metric hp"
  },
  {
   "category": "force",
   "unit": "N",
   "name": "newton",
   "value_in_base": "1",
   "base_unit": "N",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "force",
   "unit": "kN",
   "name": "kilonewton",
   "value_in_base": "1000",
   "base_unit": "N",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "force",
   "unit": "lbf",
   "name": "pound-force",
   "value_in_base": "4.4482216152605",
   "base_unit": "N",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B footnotes"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-footnotes"
   ],
   "note": ""
  },
  {
   "category": "force",
   "unit": "kgf",
   "name": "kilogram-force",
   "value_in_base": "9.80665",
   "base_unit": "N",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8",
    "NIST SP 811, Chapter 5"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8",
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-chapter-5-units-outside-si"
   ],
   "note": ""
  },
  {
   "category": "force",
   "unit": "dyn",
   "name": "dyne",
   "value_in_base": "0.00001",
   "base_unit": "N",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "force",
   "unit": "ozf",
   "name": "ounce-force",
   "value_in_base": "0.27801385095378125",
   "base_unit": "N",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "speed",
   "unit": "m/s",
   "name": "meters per second",
   "value_in_base": "1",
   "base_unit": "m/s",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "speed",
   "unit": "km/h",
   "name": "kilometers per hour",
   "value_in_base": "0.2777777777777777777777778",
   "base_unit": "m/s",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "speed",
   "unit": "mph",
   "name": "miles per hour",
   "value_in_base": "0.44704",
   "base_unit": "m/s",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "speed",
   "unit": "ft/s",
   "name": "feet per second",
   "value_in_base": "0.3048",
   "base_unit": "m/s",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "speed",
   "unit": "kn",
   "name": "knot",
   "value_in_base": "0.5144444444444444444444444",
   "base_unit": "m/s",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8",
    "NIST SP 811, Appendix B footnotes"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8",
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-footnotes"
   ],
   "note": ""
  },
  {
   "category": "speed",
   "unit": "Mach",
   "name": "Mach (sea level, ISA 15°C)",
   "value_in_base": "340.294",
   "base_unit": "m/s",
   "exact": false,
   "sources": [],
   "source_urls": [],
   "note": "no official definition; ISA sea-level speed of sound 340.294 m/s (ICAO/ISO 2533, not in allowed sources)"
  },
  {
   "category": "area",
   "unit": "mm²",
   "name": "square millimeter",
   "value_in_base": "0.000001",
   "base_unit": "m²",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "area",
   "unit": "cm²",
   "name": "square centimeter",
   "value_in_base": "0.0001",
   "base_unit": "m²",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "area",
   "unit": "m²",
   "name": "square meter",
   "value_in_base": "1",
   "base_unit": "m²",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "area",
   "unit": "km²",
   "name": "square kilometer",
   "value_in_base": "1000000",
   "base_unit": "m²",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "area",
   "unit": "in²",
   "name": "square inch",
   "value_in_base": "0.00064516",
   "base_unit": "m²",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "area",
   "unit": "ft²",
   "name": "square foot",
   "value_in_base": "0.09290304",
   "base_unit": "m²",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "area",
   "unit": "yd²",
   "name": "square yard",
   "value_in_base": "0.83612736",
   "base_unit": "m²",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "area",
   "unit": "acre",
   "name": "acre (international)",
   "value_in_base": "4046.8564224",
   "base_unit": "m²",
   "exact": true,
   "sources": [
    "NIST Handbook 44 (2026), Appendix C"
   ],
   "source_urls": [
    "https://www.nist.gov/document/2026-nist-handbook-44-appendix-c"
   ],
   "note": "international acre 4046.8564224; SP 811 (2008) lists survey acre 4046.873 (survey foot deprecated 2023-01-01 per HB44)"
  },
  {
   "category": "area",
   "unit": "ha",
   "name": "hectare",
   "value_in_base": "10000",
   "base_unit": "m²",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "time",
   "unit": "ms",
   "name": "millisecond",
   "value_in_base": "0.001",
   "base_unit": "s",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "time",
   "unit": "s",
   "name": "second",
   "value_in_base": "1",
   "base_unit": "s",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "time",
   "unit": "min",
   "name": "minute",
   "value_in_base": "60",
   "base_unit": "s",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "time",
   "unit": "h",
   "name": "hour",
   "value_in_base": "3600",
   "base_unit": "s",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "time",
   "unit": "d",
   "name": "day",
   "value_in_base": "86400",
   "base_unit": "s",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "time",
   "unit": "wk",
   "name": "week",
   "value_in_base": "604800",
   "base_unit": "s",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "time",
   "unit": "mo",
   "name": "month (30 d)",
   "value_in_base": "2592000",
   "base_unit": "s",
   "exact": false,
   "sources": [],
   "source_urls": [],
   "note": "no official month; 30 d convention (other: 365/12 d = 30.4167 d, 365.2425/12 d)"
  },
  {
   "category": "time",
   "unit": "yr",
   "name": "year (365 d)",
   "value_in_base": "31536000",
   "base_unit": "s",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": "also sidereal 31558150, tropical 31556930, Julian 365.25 d"
  },
  {
   "category": "data",
   "unit": "b",
   "name": "bit",
   "value_in_base": "0.125",
   "base_unit": "B",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "data",
   "unit": "B",
   "name": "byte",
   "value_in_base": "1",
   "base_unit": "B",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "data",
   "unit": "KB",
   "name": "kilobyte (1000)",
   "value_in_base": "1000",
   "base_unit": "B",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": "decimal"
  },
  {
   "category": "data",
   "unit": "KiB",
   "name": "kibibyte (1024)",
   "value_in_base": "1024",
   "base_unit": "B",
   "exact": true,
   "sources": [
    "NIST, prefixes for binary multiples"
   ],
   "source_urls": [
    "https://physics.nist.gov/cuu/Units/binary.html"
   ],
   "note": ""
  },
  {
   "category": "data",
   "unit": "MB",
   "name": "megabyte (1000²)",
   "value_in_base": "1000000",
   "base_unit": "B",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": "decimal"
  },
  {
   "category": "data",
   "unit": "MiB",
   "name": "mebibyte (1024²)",
   "value_in_base": "1048576",
   "base_unit": "B",
   "exact": true,
   "sources": [
    "NIST, prefixes for binary multiples"
   ],
   "source_urls": [
    "https://physics.nist.gov/cuu/Units/binary.html"
   ],
   "note": ""
  },
  {
   "category": "data",
   "unit": "GB",
   "name": "gigabyte (1000³)",
   "value_in_base": "1000000000",
   "base_unit": "B",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": "decimal"
  },
  {
   "category": "data",
   "unit": "GiB",
   "name": "gibibyte (1024³)",
   "value_in_base": "1073741824",
   "base_unit": "B",
   "exact": true,
   "sources": [
    "NIST, prefixes for binary multiples"
   ],
   "source_urls": [
    "https://physics.nist.gov/cuu/Units/binary.html"
   ],
   "note": ""
  },
  {
   "category": "data",
   "unit": "TB",
   "name": "terabyte",
   "value_in_base": "1000000000000",
   "base_unit": "B",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": "decimal"
  },
  {
   "category": "data",
   "unit": "TiB",
   "name": "tebibyte",
   "value_in_base": "1099511627776",
   "base_unit": "B",
   "exact": true,
   "sources": [
    "NIST, prefixes for binary multiples"
   ],
   "source_urls": [
    "https://physics.nist.gov/cuu/Units/binary.html"
   ],
   "note": ""
  },
  {
   "category": "angle",
   "unit": "rad",
   "name": "radian",
   "value_in_base": "1",
   "base_unit": "rad",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "angle",
   "unit": "deg",
   "name": "degree",
   "value_in_base": "0.01745329251994329576923691",
   "base_unit": "rad",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "angle",
   "unit": "grad",
   "name": "gradian",
   "value_in_base": "0.01570796326794896619231322",
   "base_unit": "rad",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "angle",
   "unit": "arcmin",
   "name": "arcminute",
   "value_in_base": "0.0002908882086657215961539485",
   "base_unit": "rad",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "angle",
   "unit": "arcsec",
   "name": "arcsecond",
   "value_in_base": "0.000004848136811095359935899141",
   "base_unit": "rad",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "angle",
   "unit": "rev",
   "name": "revolution / turn",
   "value_in_base": "6.283185307179586476925287",
   "base_unit": "rad",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "frequency",
   "unit": "Hz",
   "name": "hertz",
   "value_in_base": "1",
   "base_unit": "Hz",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "frequency",
   "unit": "kHz",
   "name": "kilohertz",
   "value_in_base": "1000",
   "base_unit": "Hz",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "frequency",
   "unit": "MHz",
   "name": "megahertz",
   "value_in_base": "1000000",
   "base_unit": "Hz",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "frequency",
   "unit": "GHz",
   "name": "gigahertz",
   "value_in_base": "1000000000",
   "base_unit": "Hz",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "frequency",
   "unit": "rpm",
   "name": "revolutions per minute",
   "value_in_base": "0.01666666666666666666666667",
   "base_unit": "Hz",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": "1 rpm = 1/60 rev/s"
  },
  {
   "category": "frequency",
   "unit": "rad/s",
   "name": "radians per second",
   "value_in_base": "0.1591549430918953357688838",
   "base_unit": "Hz",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": "SI Brochure warns frequency (Hz) and angular frequency (rad/s) must not be mixed"
  },
  {
   "category": "torque",
   "unit": "N·m",
   "name": "newton-meter",
   "value_in_base": "1",
   "base_unit": "N·m",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "torque",
   "unit": "N·cm",
   "name": "newton-centimeter",
   "value_in_base": "0.01",
   "base_unit": "N·m",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "torque",
   "unit": "kN·m",
   "name": "kilonewton-meter",
   "value_in_base": "1000",
   "base_unit": "N·m",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "torque",
   "unit": "kgf·m",
   "name": "kilogram-force meter",
   "value_in_base": "9.80665",
   "base_unit": "N·m",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "torque",
   "unit": "kgf·cm",
   "name": "kilogram-force cm",
   "value_in_base": "0.0980665",
   "base_unit": "N·m",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "torque",
   "unit": "lbf·ft",
   "name": "pound-foot",
   "value_in_base": "1.3558179483314004",
   "base_unit": "N·m",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "torque",
   "unit": "lbf·in",
   "name": "pound-inch",
   "value_in_base": "0.1129848290276167",
   "base_unit": "N·m",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "torque",
   "unit": "ozf·in",
   "name": "ounce-inch",
   "value_in_base": "0.00706155181422604375",
   "base_unit": "N·m",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "torque",
   "unit": "dyn·cm",
   "name": "dyne-centimeter",
   "value_in_base": "1E-7",
   "base_unit": "N·m",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "density",
   "unit": "kg/m³",
   "name": "kilogram per cubic meter",
   "value_in_base": "1",
   "base_unit": "kg/m³",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "density",
   "unit": "g/cm³",
   "name": "gram per cubic centimeter",
   "value_in_base": "1000",
   "base_unit": "kg/m³",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "density",
   "unit": "g/mL",
   "name": "gram per milliliter",
   "value_in_base": "1000",
   "base_unit": "kg/m³",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "density",
   "unit": "kg/L",
   "name": "kilogram per liter",
   "value_in_base": "1000",
   "base_unit": "kg/m³",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "density",
   "unit": "g/L",
   "name": "gram per liter",
   "value_in_base": "1",
   "base_unit": "kg/m³",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "density",
   "unit": "lb/ft³",
   "name": "pound per cubic foot",
   "value_in_base": "16.01846337396013957965507",
   "base_unit": "kg/m³",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "density",
   "unit": "lb/in³",
   "name": "pound per cubic inch",
   "value_in_base": "27679.90471020312119364396",
   "base_unit": "kg/m³",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "density",
   "unit": "lb/gal-us",
   "name": "pound per US gallon",
   "value_in_base": "119.8264273168966285439133",
   "base_unit": "kg/m³",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "density",
   "unit": "lb/gal-uk",
   "name": "pound per imperial gallon",
   "value_in_base": "99.77637266310169838256612",
   "base_unit": "kg/m³",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "density",
   "unit": "oz/in³",
   "name": "ounce per cubic inch",
   "value_in_base": "1729.994044387695074602748",
   "base_unit": "kg/m³",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "density",
   "unit": "slug/ft³",
   "name": "slug per cubic foot",
   "value_in_base": "515.3788183931962034410249",
   "base_unit": "kg/m³",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "flow",
   "unit": "m³/s",
   "name": "cubic meter per second",
   "value_in_base": "1",
   "base_unit": "m³/s",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "flow",
   "unit": "m³/h",
   "name": "cubic meter per hour",
   "value_in_base": "0.0002777777777777777777777778",
   "base_unit": "m³/s",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "flow",
   "unit": "L/s",
   "name": "liter per second",
   "value_in_base": "0.001",
   "base_unit": "m³/s",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "flow",
   "unit": "L/min",
   "name": "liter per minute",
   "value_in_base": "0.00001666666666666666666666667",
   "base_unit": "m³/s",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "flow",
   "unit": "L/h",
   "name": "liter per hour",
   "value_in_base": "2.777777777777777777777778e-7",
   "base_unit": "m³/s",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "flow",
   "unit": "mL/min",
   "name": "milliliter per minute",
   "value_in_base": "1.666666666666666666666667e-8",
   "base_unit": "m³/s",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "flow",
   "unit": "cfm",
   "name": "cubic feet per minute",
   "value_in_base": "0.0004719474432",
   "base_unit": "m³/s",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "flow",
   "unit": "cfs",
   "name": "cubic feet per second",
   "value_in_base": "0.028316846592",
   "base_unit": "m³/s",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "flow",
   "unit": "cfh",
   "name": "cubic feet per hour",
   "value_in_base": "0.00000786579072",
   "base_unit": "m³/s",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "flow",
   "unit": "gpm-us",
   "name": "gallon (US) per minute",
   "value_in_base": "0.0000630901964",
   "base_unit": "m³/s",
   "exact": true,
   "sources": [
    "NIST Handbook 44 (2026), Appendix C"
   ],
   "source_urls": [
    "https://www.nist.gov/document/2026-nist-handbook-44-appendix-c"
   ],
   "note": ""
  },
  {
   "category": "flow",
   "unit": "gph-us",
   "name": "gallon (US) per hour",
   "value_in_base": "0.000001051503273333333333333333",
   "base_unit": "m³/s",
   "exact": true,
   "sources": [
    "NIST Handbook 44 (2026), Appendix C"
   ],
   "source_urls": [
    "https://www.nist.gov/document/2026-nist-handbook-44-appendix-c"
   ],
   "note": ""
  },
  {
   "category": "flow",
   "unit": "gpm-uk",
   "name": "gallon (UK) per minute",
   "value_in_base": "0.00007576816666666666666666667",
   "base_unit": "m³/s",
   "exact": true,
   "sources": [
    "UK Weights and Measures Act 1985, Schedule 1"
   ],
   "source_urls": [
    "https://www.legislation.gov.uk/ukpga/1985/72/schedule/1/enacted"
   ],
   "note": ""
  },
  {
   "category": "flow",
   "unit": "bbl/d",
   "name": "oil barrel per day",
   "value_in_base": "0.000001840130728333333333333333",
   "base_unit": "m³/s",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "acceleration",
   "unit": "m/s²",
   "name": "meter per second squared",
   "value_in_base": "1",
   "base_unit": "m/s²",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "acceleration",
   "unit": "cm/s²",
   "name": "cm per second squared",
   "value_in_base": "0.01",
   "base_unit": "m/s²",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "acceleration",
   "unit": "ft/s²",
   "name": "foot per second squared",
   "value_in_base": "0.3048",
   "base_unit": "m/s²",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "acceleration",
   "unit": "in/s²",
   "name": "inch per second squared",
   "value_in_base": "0.0254",
   "base_unit": "m/s²",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "acceleration",
   "unit": "g",
   "name": "gram",
   "value_in_base": "9.80665",
   "base_unit": "m/s²",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "acceleration",
   "unit": "gal",
   "name": "galileo (gal, cm/s²)",
   "value_in_base": "0.01",
   "base_unit": "m/s²",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "acceleration",
   "unit": "mg-acc",
   "name": "milli-g (1/1000 g)",
   "value_in_base": "0.00980665",
   "base_unit": "m/s²",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "acceleration",
   "unit": "km/h/s",
   "name": "km/h per second",
   "value_in_base": "0.2777777777777777777777778",
   "base_unit": "m/s²",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "acceleration",
   "unit": "mph/s",
   "name": "mph per second",
   "value_in_base": "0.44704",
   "base_unit": "m/s²",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "viscosity",
   "unit": "Pa·s",
   "name": "pascal-second",
   "value_in_base": "1",
   "base_unit": "Pa·s",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "viscosity",
   "unit": "mPa·s",
   "name": "millipascal-second",
   "value_in_base": "0.001",
   "base_unit": "Pa·s",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "viscosity",
   "unit": "P",
   "name": "poise",
   "value_in_base": "0.1",
   "base_unit": "Pa·s",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "viscosity",
   "unit": "cP",
   "name": "centipoise",
   "value_in_base": "0.001",
   "base_unit": "Pa·s",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "viscosity",
   "unit": "kg/(m·s)",
   "name": "kg per meter-second",
   "value_in_base": "1",
   "base_unit": "Pa·s",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "viscosity",
   "unit": "lbf·s/ft²",
   "name": "pound-force·s / ft²",
   "value_in_base": "47.88025898033584261612968",
   "base_unit": "Pa·s",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "viscosity",
   "unit": "lbf·s/in²",
   "name": "reyn (lbf·s / in²)",
   "value_in_base": "6894.757293168361336722673",
   "base_unit": "Pa·s",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "viscosity",
   "unit": "lb/(ft·s)",
   "name": "pound per foot-second",
   "value_in_base": "1.488163943569553805774278",
   "base_unit": "Pa·s",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "luminance",
   "unit": "lx",
   "name": "lux (lumen / m²)",
   "value_in_base": "1",
   "base_unit": "lx",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "luminance",
   "unit": "fc",
   "name": "foot-candle (lumen / ft²)",
   "value_in_base": "10.76391041670972230833351",
   "base_unit": "lx",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "luminance",
   "unit": "ph",
   "name": "phot (lumen / cm²)",
   "value_in_base": "10000",
   "base_unit": "lx",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "luminance",
   "unit": "nox",
   "name": "nox (1/1000 lux)",
   "value_in_base": "0.001",
   "base_unit": "lx",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "luminance",
   "unit": "lm/m²",
   "name": "lumen per m² (= lux)",
   "value_in_base": "1",
   "base_unit": "lx",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "luminance",
   "unit": "lm/ft²",
   "name": "lumen per ft²",
   "value_in_base": "10.76391041670972230833351",
   "base_unit": "lx",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "concentration",
   "unit": "mg/L",
   "name": "milligram per liter",
   "value_in_base": "1",
   "base_unit": "mg/L",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "concentration",
   "unit": "µg/L",
   "name": "microgram per liter",
   "value_in_base": "0.001",
   "base_unit": "mg/L",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "concentration",
   "unit": "g/L",
   "name": "gram per liter",
   "value_in_base": "1000",
   "base_unit": "mg/L",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "concentration",
   "unit": "kg/L",
   "name": "kilogram per liter",
   "value_in_base": "1000000",
   "base_unit": "mg/L",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "concentration",
   "unit": "ppm",
   "name": "parts per million (mg/L in water)",
   "value_in_base": "1",
   "base_unit": "mg/L",
   "exact": false,
   "sources": [],
   "source_urls": [],
   "note": "ppm = mg/L only for dilute aqueous solutions (density 1 kg/L); SP 811 discourages ppm"
  },
  {
   "category": "concentration",
   "unit": "ppb",
   "name": "parts per billion (µg/L in water)",
   "value_in_base": "0.001",
   "base_unit": "mg/L",
   "exact": false,
   "sources": [],
   "source_urls": [],
   "note": "as ppm"
  },
  {
   "category": "concentration",
   "unit": "ppt",
   "name": "parts per trillion (ng/L)",
   "value_in_base": "0.000001",
   "base_unit": "mg/L",
   "exact": false,
   "sources": [],
   "source_urls": [],
   "note": "ppt ambiguous (trillion vs thousand)"
  },
  {
   "category": "concentration",
   "unit": "%w/v",
   "name": "percent weight/volume (g/100mL)",
   "value_in_base": "10000",
   "base_unit": "mg/L",
   "exact": true,
   "sources": [],
   "source_urls": [],
   "note": ""
  },
  {
   "category": "concentration",
   "unit": "g/100mL",
   "name": "gram per 100 mL",
   "value_in_base": "10000",
   "base_unit": "mg/L",
   "exact": true,
   "sources": [
    "BIPM SI Brochure, 9th ed."
   ],
   "source_urls": [
    "https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf"
   ],
   "note": ""
  },
  {
   "category": "concentration",
   "unit": "oz/gal-us",
   "name": "ounce per US gallon (mass)",
   "value_in_base": "7489.151707306039283994578",
   "base_unit": "mg/L",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  },
  {
   "category": "concentration",
   "unit": "gr/gal-us",
   "name": "grain per US gallon",
   "value_in_base": "17.11806104527094693484475",
   "base_unit": "mg/L",
   "exact": true,
   "sources": [
    "NIST SP 811, Appendix B.8"
   ],
   "source_urls": [
    "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
   ],
   "note": ""
  }
 ]
}