How the Weight Converter works
Each unit is defined as an exact fraction of a kilogram. The imperial and US units are based on the international pound, defined in 1959 as exactly 0.45359237 kg. From it: an ounce is 1/16 lb (28.349523125 g), a stone is 14 lb (6.35029318 kg), a US short ton is 2,000 lb (907.18474 kg) and a UK long ton is 2,240 lb (1,016.0469088 kg). A metric tonne is 1,000 kg.
The converter multiplies your value by the ratio of the two definitions and rounds the result in decimal to the number of significant digits you choose, so there is no floating point noise such as 0.30000000000000004. The stone and pounds and the pounds and ounces lines round the smaller unit to two decimals first, so they never show 14 lb or 16 oz.
Strictly speaking these are units of mass. In everyday use "weight" means the same thing, and the numbers are identical.
How to use the Weight Converter
- Type a weight in the Weight box, for example 70 or 0.5.
- Choose the unit it is in from the From unit list.
- Choose the precision in significant digits.
- Read the table of every unit with its exact definition, and the stone and pounds and pounds and ounces lines. Results update as you type.
- Select Copy next to a value to copy it.
Example
Entering 70 with Kilograms (kg) selected gives, among others:
Grams (g) 70,000
Ounces (oz) 2,469.177336
Pounds (lb) 154.3235835
Stone (st) 11.02311311
Stone and pounds 11 st 0.32 lb
Pounds and ounces 154 lb 5.18 ozEntering 1 with Pounds (lb) selected gives exactly 0.45359237 kg and 453.59237 g.
Common use cases
- Converting body weight between kilograms, pounds and stone.
- Following recipes that use ounces or grams.
- Calculating shipping weights for parcels and freight in pounds, kilograms or tons.
- Converting product specifications between metric and US units.
Frequently asked questions
How many kilograms are in a pound?
Exactly 0.45359237. This value was agreed internationally in 1959 and is used by the US and the UK. One kilogram is about 2.20462 pounds.
How many pounds are in a stone?
Fourteen. A stone is 6.35029318 kg. It is still commonly used for body weight in the UK and Ireland.
What is the difference between a tonne, a short ton and a long ton?
A metric tonne is 1,000 kg. A US short ton is 2,000 lb (907.18474 kg). A UK long ton is 2,240 lb (1,016.0469088 kg).
Which ounce does the converter use?
The avoirdupois ounce, 1/16 of a pound or 28.349523125 g, which is used for food and everyday goods. Troy ounces used for precious metals (31.1034768 g) are not included.
Is this weight or mass?
All these units measure mass. In everyday language weight means the same thing, and the numbers are identical on Earth.