Weight Converter

Convert pounds, ounces, stone and tons to kilograms, grams and tonnes, plus troy ounces, grains and carats.

Decimals, fractions (3 1/2) and e-notation (1.5e6) all work.
Common Conversions
Significant Digits
Result
Formula
Reverse
Exact?

In Every Unit

UnitValue

Saved Conversions

Conversions you add are saved in this browser.

NoteConversionRemove

How to Convert Weight Units

The pound has been defined as exactly 0.45359237 kilograms since 1959. An ounce is 1/16 of a pound, a stone is 14 pounds and a US ton is 2,000 pounds.

kg = lb × 0.45359237   g = oz × 28.349523125

Worked Example

Common Conversions

FromEquals
1 lb0.4535924 kg
1 kg2.204623 lb
1 oz28.34952 g
1 g0.03527396 oz
1 st6.350293 kg
1 ton0.9071847 t
1 oz t31.10348 g

Unit Definitions

UnitEqualsExact?
Micrograms (µg)1 × 10⁻⁹ kgExact
Milligrams (mg)0.000001 kgExact
Grams (g)0.001 kgExact
Kilograms (kg)1 kgExact
Metric tons (tonnes) (t)1,000 kgExact
Grains (gr)0.00006479891 kgExact
Carats (ct)0.0002 kgExact
Ounces (oz)0.02834952313 kgExact
Pounds (lb)0.45359237 kgExact
Stone (st)6.35029318 kgExact
US short tons (ton)907.18474 kgExact
UK long tons (long ton)1,016.046909 kgExact
Troy ounces (oz t)0.0311034768 kgExact
Pennyweights (dwt)0.00155517384 kgExact

Factors follow NIST Special Publication 811, Appendix B. "Exact" means the unit is defined as that value; results are rounded only for display.

Tips

Troy ounces (used for gold and silver) are about 10% heavier than ordinary ounces: 31.1035 g vs 28.3495 g. "Weight" here means mass, which is what scales report.