Weight Converter
Body weight, parcels, recipes, bulk materials — weight conversion crosses borders daily. This weight converter translates between kilograms, grams, milligrams, metric tonnes, pounds, ounces, stones and US tons using exact definitions.
The pound is defined as exactly 0.45359237 kg, so conversions here are precise to the last digit shown.
Enter valid values to see the results.
Formula
Key anchors: 1 lb = 0.4536 kg, 1 oz = 28.35 g, 1 stone = 14 lb = 6.35 kg, 1 metric tonne = 1,000 kg = 2,204.6 lb. A US ton (2,000 lb) is 907 kg — smaller than a metric tonne.
What you need
- Enter the weight and choose the source and target units.
- Stones are used for body weight in the UK and Ireland: 1 st = 14 lb.
- For bulk materials like gravel and sand, suppliers quote tonnes or US tons — check which one your quote means.
Worked example
Practical tips
- Quick anchor: 1 kg ≈ 2.2 lb — double and add 10% for a mental estimate.
- For parcels, carriers often bill by the greater of actual and volumetric weight — check both.
- Gold and precious metals use troy ounces (31.1 g), not the 28.35 g avoirdupois ounce.
- Recipe conversions: 1 oz ≈ 28 g, 100 g ≈ 3.5 oz — close enough for cooking, not for baking chemistry.
Weight conversion quick reference
| Unit | In kilograms | Common use |
|---|---|---|
| 1 ounce | 0.0283 kg | Cooking, parcels |
| 1 pound | 0.4536 kg | Body weight (US) |
| 1 stone | 6.3503 kg | Body weight (UK) |
| 1 US ton | 907.18 kg | Bulk materials (US) |
Common mistakes
- 1 Confusing metric tonnes (1,000 kg) with US tons (907 kg) in material orders — an 10% shortfall.
- 2 Mixing troy and avoirdupois ounces for precious metals.
- 3 Rounding 1 lb to 0.45 kg accumulates a 0.8% error — visible on large quantities.
Frequently asked questions
How many pounds are in a kilogram?
1 kg = 2.20462 lb. To convert pounds to kilograms, multiply by 0.4536.
What is a stone in kilograms?
1 stone = 14 pounds = 6.35029 kg. Someone weighing 11 st 5 lb weighs 72.1 kg.
Is a US ton the same as a tonne?
No. A US (short) ton is 2,000 lb = 907.18 kg; a metric tonne is 1,000 kg = 2,204.6 lb. The UK long ton is 1,016 kg.
How many grams are in an ounce?
28.3495 g for the standard (avoirdupois) ounce. The troy ounce used for gold is 31.1035 g.