Weight Converter
Convert weight and mass between kilograms, grams, milligrams, tonnes, pounds, ounces and stone — instantly, in both directions.
How weight conversion works
All the units here are defined in terms of the kilogram, so every conversion is exact: the value is first
expressed in kilograms, then in the target unit. The imperial units have had exact metric definitions since
1959:
- 1 pound (lb) = 0.45359237 kg exactly · 1 ounce = 1/16 lb = 28.349523 g
- 1 stone = 14 lb = 6.35029318 kg · 1 tonne (metric) = 1,000 kg
Kilograms dominate science and most of the world’s scales; pounds and ounces persist in the US, and stone is
still the everyday body-weight unit in the UK and Ireland (an adult might say they weigh “11 stone 4”, meaning
11 st 4 lb ≈ 71.7 kg).
Handy approximations
- kg → lb: multiply by 2.2 (70 kg ≈ 154 lb)
- lb → kg: divide by 2.2, or halve it and add 10% back (160 lb ≈ 72.6 kg)
- stone → kg: multiply by 6.35 (10 st ≈ 63.5 kg)
- oz → g: multiply by 28 (4 oz ≈ 113 g)
Worked example
Converting 70 kg to pounds: 70 ÷ 0.45359237 = 154.32 lb. In stone that is
154.32 ÷ 14 = 11 st 0.3 lb — which is why 70 kg is often quoted as “about 11 stone”.
Frequently asked questions
How many pounds are in a kilogram?
1 kg = 2.20462 lb (the pound is defined as exactly 0.45359237 kg). So 70 kg ≈ 154.3 lb, and to go the other way divide pounds by 2.2046.
How many kg is 12 stone?
1 stone = 14 lb = 6.35029 kg exactly, so 12 stone = 76.2 kg. A common body-weight range of 10–14 stone corresponds to roughly 63.5–88.9 kg.
How many grams are in an ounce?
1 ounce (avoirdupois) = 28.3495 g exactly. So 100 g ≈ 3.53 oz, and a "quarter pound" (4 oz) is about 113 g.
What is the difference between a tonne and a US ton?
This converter uses the metric tonne: exactly 1,000 kg (about 2,204.6 lb). A US "short ton" is 2,000 lb ≈ 907.2 kg, and a UK "long ton" is 2,240 lb ≈ 1,016 kg — so always check which ton is meant.
Is weight the same as mass?
Strictly, kilograms and pounds here measure mass — the amount of matter — which does not change with location. Weight is the force gravity exerts on that mass. In everyday use (and on this page) "weight" means mass, the number your scale shows.