Convert any weight instantly across milligrams, grams, kilograms, tonnes, ounces, pounds, stone, US tons, long tons, carats and grains — with exact international constants.
Enter the amount to convert (commas allowed, e.g. 1,234.5)
All conversions go through kilograms using exact definitions of the avoirdupois pound and related units. Enter a value, choose the from unit, and read every unit at once. Decimal places are adjustable from 0 to 10 (default 4), and very small or very large results switch to scientific notation automatically.
1 lb = 0.45359237 kg (exact) 1 oz = 1/16 lb 1 stone = 14 lb 1 US ton = 2000 lb 1 long ton = 2240 lb 1 tonne (metric) = 1000 kg 1 carat = 0.2 g 1 grain = 64.79891 mg
1 kg = 2.20462 lb (to 5 d.p.) and ≈ 35.27396 oz.
1 US ton = 2000 × 0.45359237 = 907.18474 kg. 1 long ton = 2240 × 0.45359237 ≈ 1016.0469 kg.
The international avoirdupois pound is defined as exactly 0.45359237 kilograms. Every imperial mass unit on this page derives from that constant: an ounce is one sixteenth of a pound, a stone is fourteen pounds, a US (short) ton is 2000 pounds, and a long (UK) ton is 2240 pounds. Metric units are simpler — 1000 mg = 1 g, 1000 g = 1 kg, 1000 kg = 1 tonne. Jewellery carats are 0.2 g each; the grain (used in ballistics and pharmacy history) is 64.79891 mg.
To convert from unit A to unit B, multiply by the A→kg factor, then divide by the B→kg factor. That two-step path avoids rounding drift between irregular pairs and matches what this converter shows in the all-units result table.
| Unit | Equals |
|---|---|
| Milligrams (mg) | 1.00000000e+6 per kg |
| Grams (g) | 1000.00000000 per kg |
| Kilograms (kg) | 1.00000000 per kg |
| Tonnes (metric, t) | 0.00100000 per kg |
| Ounces (oz) | 35.27396195 per kg |
| Pounds (lb) | 2.20462262 per kg |
| Stone (st) | 0.15747304 per kg |
| US ton (short ton) | 0.00110231 per kg |
| Long ton (UK) | 0.00098421 per kg |
| Carats (ct) | 5000.00000000 per kg |
| Grains (gr) | 15432.35835294 per kg |
Related tools: Pounds to Kilograms Converter · Stones to Kilograms Converter
Exactly 1 kg = 1 / 0.45359237 lb ≈ 2.2046226218 lb. This converter uses the international avoirdupois pound definition.
1 kg ≈ 35.27396195 oz, since 1 oz = 1/16 lb and 1 lb = 0.45359237 kg.
A US (short) ton is 2000 lb ≈ 907.18474 kg. A long (UK) ton is 2240 lb ≈ 1016.0469 kg. A metric tonne is exactly 1000 kg.
1 stone = 14 lb = 14 × 0.45359237 kg = 6.35029318 kg. For stones-and-pounds input, try the Stones to Kilograms converter.
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