Open data.

Files

• units.csv — Units and their definitions. Every unit with a fixed factor: its value in the base unit of its category, whether the definition is exact, and the official source. The temperature scales and fuel-economy units are defined by formulas, given in units.json. 183 rows · Source: NIST SP 811, NIST Handbook 44, BIPM SI Brochure, NIST binary prefixes, UK Weights and Measures Act 1985
• conversions.csv — Converter factors. One row per converter page: multiply the 'from' value by the factor to get the 'to' value. Temperature pairs use the formulas in units.json. 109 rows · Source: Derived with exact arithmetic from units.csv
• conversion-values.csv — Common conversion values. The values that have their own page on the site (for example 37 °C in °F), converted with the factors above. 146 rows · Source: Computed from conversions.csv
• awg.csv — AWG wire geometry. Diameter and cross-section of American Wire Gauge sizes 4/0 to 40, from the defining formula d = 0.005 in × 92^((36 − n)/39) (ASTM B258). Ampacity is not included. 44 rows · Source: Computed from the AWG formula (ASTM B258)
• npt-threads.csv — NPT pipe thread basic dimensions. American Standard taper pipe threads (NPT): threads per inch, outside diameter, pitch diameters E0 and E1, hand-tight engagement L1 and effective thread length L2, in inches. 14 rows · Source: NBS Handbook H28 (1957), Part II, Table VII.2 (US government publication, public domain); checked 7 November 2026
• water-density.csv — Density of pure water, 0–40 °C. Density of air-free pure water at 101.325 kPa and the weight of one US gallon, from the CIPM-recommended formula. 41 rows · Source: CIPM formula, Tanaka et al., Metrologia 38 (2001) 301–309, as published by NIST
• boiling-point-altitude.csv — Boiling point of water by altitude. Standard-atmosphere pressure and the boiling point of pure water from sea level to 8,849 m. 37 rows · Source: IAPWS R7-97(2012) Region 4 equation; U.S. Standard Atmosphere, 1976
• wind-chill.csv — Wind chill table. Wind chill temperature in °F for air temperatures from 40 °F to −45 °F and wind speeds from 5 to 60 mph. 216 rows · Source: National Weather Service wind chill formula (2001)
• tasks.json — Task paths. Common engineering jobs as ordered steps across the site's pages. 23 records · Source: unitcheatsheet.com
• verification.json — Verification records. What was checked against which official source, when, for which pages. 16 records · Source: unitcheatsheet.com

Also: units.json (units with sources, plus the temperature and fuel-economy formulas), datapackage.json (Frictionless Data descriptor), README, CITATION.cff. Every file can be fetched from other sites and tools (CORS is open), so the folder also works as a simple read-only API: https://unitcheatsheet.com/data/conversions.csv. The same files, with their version history, are on GitHub.

Licence and attribution

The data is licensed under Creative Commons Attribution 4.0 (CC BY 4.0). You can copy, adapt and use it, including commercially, if you credit it as: “unitcheatsheet.com open data (https://unitcheatsheet.com/data.html), CC BY 4.0”. Values from public-domain sources (NIST, NBS, NWS) stay in the public domain.

What is not included

Tables taken from copyrighted or paid standards and handbooks — NEC ampacity, ISO tolerances, ANSI drill sizes, SAE O-rings, Machinery's Handbook tap drills, the CDA Copper Tube Handbook — are shown on the site with their sources, but no licence to them is offered here.

Accuracy

Conversion factors are checked against NIST and BIPM with exact arithmetic; verification.json lists what was checked against which source and when. Found an error? Email contactus@unitcheatsheet.com; fixes are listed in the changelog.