Weight unit converter
Convert between tonnes, kilos, grams, pounds, ounces and stones.
Calculator inputs
Results
Enter your values and press “Calculate” to see the result.
In short
- What it calculates
- Convert between tonnes, kilos, grams, pounds, ounces and stones.
- Formula used
result = value × (source factor ÷ target factor)- Example
- 1 kilogram in other units:
Weight and mass converter
It covers everything from the milligram to the tonne, including the imperial units that turn up on labels and international shipments.
How it works
Each unit has an exact factor relative to the kilogram. The value is converted to kilograms and from there to the unit you choose.
Formula
result = value × (source factor ÷ target factor)
1 t = 1000 kg · 1 lb = 0.45359237 kg
1 oz = 0.028349523 kg · 1 st = 6.35029318 kg
Worked example
1 kilogram in other units:
2.2046 pounds
35.274 ounces
0.1575 stones
1000 grams
Explanation
The kilogram stopped being a cylinder in 2019
Until then, the kilogram was the mass of a platinum-iridium cylinder kept in France since 1889. The problem was that it slowly lost mass and there was no way to know for certain, because it was its own reference. Since 2019 it has been defined from the Planck constant, and no longer depends on any object.
The ton comes in three versions
The metric tonne is a thousand kilos. The American short ton is 907 kg and the British long ton 1,016 kg. In international trade, confusing them changes the price of a cargo substantially, which is why contracts always specify which applies.
Carats and metals
The metric carat is exactly 200 milligrams and is used for gemstones. Do not confuse it with the karat of gold purity, which is a proportion out of twenty-four and not a mass. An eighteen-karat ring does not weigh eighteen carats: it is three quarters gold.
Net, drained and gross weight
In food labelling, net weight includes the packing liquid and drained weight does not. Comparing two tins by net weight can mislead if one carries more liquid than the other.
Frequently asked questions
Are weight and mass the same?
Not in physics: mass is constant while weight depends on gravity. In everyday use they are treated as synonyms, and these units measure mass.
What is a stone?
A British unit of 14 pounds, used mainly for body weight in the UK and Ireland.
Do all tons weigh a thousand kilos?
No. The metric tonne does, but the American short ton is 907 kg and the British long ton 1,016 kg.
Is the karat of gold a unit of weight?
Not in that use. Purity karat is a proportion out of twenty-four. The metric carat, used for gemstones, is 200 milligrams.
Need to calculate something else?
These tools are often used alongside this calculator.
Kg to pounds
Turn any weight from kilograms into pounds with the exact international factor.
Pounds to kg
Convert weights in pounds into the metric system exactly.
Volume
Litres, millilitres, gallons, pints, cups and spoons in a single tool.
Km to miles
Turn any distance from kilometres into statute miles using the official factor.
Celsius to Fahrenheit
Turn any temperature from the Celsius scale into Fahrenheit.
Currency
Convert between 34 currencies at today’s rate and see the inverse equivalence.