Weight Converter

The international pound is defined as exactly 0.45359237 kilograms, so 1 stone (14 lb) equals 6.35029318 kg and 11 stone (154 lb) equals about 69.85 kg. Every other unit here, from milligrams to tonnes, converts through this single exact ratio.

Tip: “Copy with settings” shares a link that opens this calculator with your numbers already filled in.

How this calculator works

Pick a from-unit and a to-unit and type a value; the conversion and the exact factor for that pair appear instantly. Stone (st) is included alongside the metric and US/imperial units because it remains the everyday unit for body weight in the UK and Ireland, where 1 stone equals 14 pounds.

Every unit here is defined in kilograms, so any pair converts through a single exact ratio with no rounding chain to accumulate error. The international avoirdupois pound, the basis for ounces, pounds and stone, has been fixed at exactly 0.45359237 kg since the 1959 international yard and pound agreement.

How it converts

result = value × (kilograms per from-unit) ÷ (kilograms per to-unit)

Exact anchors: 1 lb = 0.45359237 kg · 1 oz = 1⁄16 lb = 0.028349523125 kg · 1 st = 14 lb = 6.35029318 kg · 1 tonne = 1,000 kg

Worked example: 11 stone to kilograms

11 stone × 14 lb/stone = 154 lb.
154 lb × 0.45359237 kg/lb = 69.85322498 kg.
So 11 stone is about 69.85 kg, or roughly 69,853 grams.

Frequently asked questions

How many pounds are in a stone?

Exactly 14 pounds. Stone is still the common unit for adult body weight in the UK and Ireland, usually written as, for example, '11 stone 6 lb'.

Is a metric tonne the same as a US ton?

No. A metric tonne is exactly 1,000 kg (about 2,204.6 lb). A US 'short ton' is 2,000 lb (about 907.18 kg) and a UK 'long ton' is 2,240 lb (about 1,016.05 kg). This converter uses the metric tonne.

Why do ounces here mean weight, not volume?

This is the avoirdupois ounce (1/16 pound, used for body weight, food packaging and postage), not the US fluid ounce, which measures volume. Use the volume converter for fluid ounces.

How precise are these conversions?

All the anchor factors (pound, ounce, stone, tonne) are exact by definition, so the math introduces no rounding error. Round the displayed result to match the precision of your scale.

How do I convert kilograms to pounds without a calculator?

Multiply the kilogram value by about 2.20462, or divide by 0.45359237, the exact kg-per-pound value this page uses. Reversing the worked example confirms it: 69.85322498 kg ÷ 0.45359237 = 154 lb, the same 154 lb (11 stone) it started from.