Convert stone to kilogram.

Convert stone (st) to kilogram (kg). This is a fixed-ratio conversion — multiply the input by the factor below.

Formula

kg = st × 6.35029

Reference values

Things to watch for

• Mass and weight aren't the same thing. Pounds usually mean mass in everyday use, but force in engineering — context matters.
• The international avoirdupois pound is 0.45359237 kg (exact). Don't confuse with troy pound (0.3732 kg, used for precious metals).
• Metric tons (1000 kg) differ from US short tons (907.185 kg) and UK long tons (1016 kg). Always specify which.

What is a stone?

One stone equals exactly 14 pounds or about 6.35 kilograms. Body weight in the UK and Ireland.

What is a kilogram?

The kilogram is the SI base unit of mass, defined since 2019 by fixing the Planck constant. Body weight, groceries, freight, and most everyday weight measurements outside the US.

How to picture a st

Here are a few familiar reference points to gauge the unit. 1 st is about the weight of a medium dog; 11 st is roughly an average adult body weight.

How to convert stone to kilogram

To convert a value from stone (st) to kilogram (kg), apply the conversion factor shown in the formula above. The calculation is the same whether you do it by hand, in a spreadsheet, or with the live converter on this page.

Steps:

1. Take your input value in st.
2. Apply the formula kg = st × 6.35029.
3. The result is your value in kg.

For repeated calculations, save the formula in a spreadsheet or use the live converter at the top of this page — it handles the math automatically and displays the result as you type.

Frequently asked questions

How do I convert st to kg?

Apply the formula st → kg shown above, or just type your value into the converter at the top of this page. The result updates instantly.

Which is bigger, st or kg?

This depends on the conversion ratio in the formula. If the factor multiplied by your value gives a larger number, then kg is the smaller unit (so it takes more of them to express the same quantity). If the result is smaller, then kg is the larger unit.

When would I use st versus kg?

Both units measure mass, so the choice depends on context. Stone is typically used for shipping, scientific measurement, cooking, and commerce; kilogram similarly. Most professional fields standardize on one or the other based on regional conventions or technical tradition.

How precise is this st to kg conversion?

The conversion factor shown is the internationally defined exact value (or the best-published approximation if the relationship is irrational, like degrees-to-radians). The live converter on this page uses double-precision floating-point math, accurate to about 15 significant digits — far beyond any practical engineering need.

Is the conversion ratio exact, or an approximation?

Most unit conversions between SI metric units, and between SI and US customary units, have been formally defined as exact values since the 1959 international yard-pound agreement and subsequent SI redefinitions. Exceptions are unit pairs that involve irrational numbers (radians, e.g.) or empirical conversions (like food calories, which depend on temperature). When in doubt, consult the formula at the top of this page.

Related conversions

See also