What this weight converter does
This tool converts weight (mass) between the six units that cover nearly every everyday situation: grams (g) and kilograms (kg) from the metric system; ounces (oz), pounds (lb) and tonnes from daily American and international use; and stone (st), still the everyday unit for body weight in Britain and Ireland. It converts in both directions, updates as you type, and shows your figure in all six units at once below the main result — helpful when a recipe, a luggage limit and a shipping label all insist on different units.
Weight conversions are where small errors stop being harmless. A recipe that calls for 500 grams of flour is not the same as a pound of flour (a pound is about 454 grams, nearly 10% less). An airline baggage limit of 23 kg is 50.7 lb, not a round 50. A baby's birth weight, a dog's medication dose by weight, gym plates marked in kilograms on one side of the Atlantic and pounds on the other — all of these are routine conversions where getting the factor right matters, and where guessing "a kilo is about two pounds" quietly introduces a 10% error. This converter uses the exact international definitions, so the number you see is the number a scale manufacturer, airline or pharmacist would use.
How to use it
- Type the weight into the From box.
- Pick the unit you have, then the unit you want.
- Read the result. Press Swap to reverse direction instantly, and use the table below for the same weight in every unit.
The conversion factors
The international pound is defined as exactly 0.45359237 kilograms, and everything else on this page follows from the definitions of the units themselves:
| Unit | Equals (in kilograms) | Useful equivalents |
|---|---|---|
| Gram (g) | 0.001 kg | 1,000 g = 1 kg |
| Kilogram (kg) | 1 kg | 1 kg ≈ 2.20462 lb |
| Ounce (oz) | 0.028349523125 kg | 16 oz = 1 lb |
| Pound (lb) | 0.45359237 kg | 14 lb = 1 stone |
| Stone (st) | 6.35029318 kg | 1 st = 14 lb |
| Tonne (t) | 1,000 kg | 1 t ≈ 2,204.62 lb |
Worked examples
- Airline luggage: a 23 kg checked-bag limit is 23 × 2.20462 ≈ 50.7 lb — so a bag that weighs 50 lb at home is within the limit, with a little room to spare.
- Baking: 250 g of butter is about 8.82 oz — a little more than two standard American sticks (one stick is 4 oz / 113 g).
- Body weight: 11 stone is 154 lb, or about 69.85 kg — the three figures a British, American and European form would each ask for.
- A new baby: 3.4 kg is about 7 lb 8 oz — the conversion every family with relatives on both sides of the Atlantic ends up doing.
Weight, mass and "tons" — three honest warnings
First, everyday language says "weight" where science says "mass": the kilogram and pound both measure the amount of matter, and for anything you will ever weigh on Earth the distinction makes no practical difference, which is why this page follows everyday usage. Second, beware fluid ounces: a fluid ounce measures volume, not weight, and 8 fl oz of water weighs about 8.3 oz while 8 fl oz of flour weighs far less. This converter handles weight ounces only. Third, a tonne (1,000 kg, used here) is not a US short ton (2,000 lb ≈ 907.2 kg) or a British long ton (2,240 lb ≈ 1,016 kg). If a shipping or hauling quote just says "tons", ask which one before you rely on the number.
Frequently asked questions
How many pounds are in a kilogram?
About 2.20462. Multiply kilograms by 2.20462 to get pounds; multiply pounds by 0.45359237 to get kilograms.
How many ounces are in a pound?
Exactly 16 — and 14 pounds make one stone.
What is a stone in kilograms?
One stone is 6.35029 kg (exactly 14 lb).
Is a tonne the same as a ton?
No. A tonne is 1,000 kg. A US short ton is 2,000 lb (about 907 kg) and a British long ton is 2,240 lb (about 1,016 kg).
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