UnitSnapWeight converter
This category covers mass, commonly called weight in everyday speech. The SI base unit is the kilogram. Since the 2019 SI redefinition, the kilogram is defined by fixing the numerical value of the Planck constant, replacing the platinum-iridium prototype kept near Paris that had served as the standard since 1889.
Convert between 13 weight units. Pick any two units below; results update as you type.
Popular weight conversions
- Kilograms to Pounds
- Pounds to Kilograms
- Grams to Ounces
- Ounces to Grams
- Pounds to Ounces
- Ounces to Pounds
- Stone to Kilograms
- Kilograms to Stone
- Stone to Pounds
- Pounds to Stone
- Metric Tons to Short Tons (US)
- Short Tons (US) to Metric Tons
- Short Tons (US) to Kilograms
- Kilograms to Short Tons (US)
- Kilograms to Grams
- Grams to Kilograms
- Milligrams to Grams
- Grams to Milligrams
- Troy Ounces to Grams
- Grams to Troy Ounces
- Carats to Grams
- Grams to Carats
- Grains to Milligrams
- Milligrams to Grains
About weight units
Metric units (milligram, gram, kilogram, tonne) dominate worldwide. The US uses avoirdupois pounds and ounces, and the UK still uses stones for body weight. "Ton" is ambiguous: the US short ton is 2,000 lb, the UK long ton is 2,240 lb, and the metric tonne is 1,000 kg. The UK hundredweight (cwt) is 112 lb, while the US hundredweight is 100 lb.
The international avoirdupois pound is exactly 0.45359237 kg, and 1 stone is 14 lb. Precious metals use the troy ounce, exactly 31.1034768 g, which is heavier than the 28.349523125 g avoirdupois ounce. Gemstones use the metric carat of exactly 200 mg, and the grain is exactly 64.79891 mg.
Tips
- Gold and silver prices are quoted per troy ounce, not the ordinary ounce used for food; mixing them up causes an error of nearly 10%.
- A kilogram is roughly 2.2 pounds, a good mental shortcut for body weight and luggage.
- Check which ton a document means: shipping and US industry often use short tons, while most international statistics use metric tonnes.
All weight units
| Unit | Symbol | Value in kilograms |
|---|---|---|
| Milligrams | mg | 1 mg = 0.000001 kg |
| Grams | g | 1 g = 0.001 kg |
| Kilograms | kg | 1 kg = 1 kg |
| Pounds | lb | 1 lb = 0.4535924 kg |
| Ounces | oz | 1 oz = 0.02834952 kg |
| Troy Ounces | oz t | 1 oz t = 0.03110348 kg |
| Grains | gr | 1 gr = 0.00006479891 kg |
| Metric Tons | t | 1 t = 1,000 kg |
| Long Tons (UK) | long tn | 1 long tn = 1,016.047 kg |
| Short Tons (US) | sh tn | 1 sh tn = 907.1847 kg |
| Stone | st | 1 st = 6.350293 kg |
| Long Hundredweight | cwt | 1 cwt = 50.80235 kg |
| Carats | ct | 1 ct = 0.0002 kg |
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Factors: NIST SP 811 · SI Brochure · NIST Handbook 44 — Updated