Weight and Mass Converter
Kilograms, pounds, ounces, stone and tonnes — converted with exact definitions and the arithmetic shown.
Weight and Mass Converter
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Units in this category
| Unit | Symbol | Exactly |
|---|---|---|
| kilograms (kg) | kg | reference unit for this category |
| grams (g) | g | 0.001 kg |
| milligrams (mg) | mg | 0.000001 kg |
| metric tonnes (t) | t | 1,000 kg |
| pounds (lb) | lb | 0.45359237 kg |
| ounces (oz) | oz | 0.02834952 kg |
| stone (st) | st | 6.350293 kg |
Where these factors come from
The avoirdupois pound is defined as exactly 0.45359237 kg (1959), so pounds, ounces (1/16 lb) and stone (14 lb) all convert exactly. The metric tonne is exactly 1000 kg by definition.
All 42 weight and mass pairs
| from → to | kg | g | mg | t | lb | oz | st |
|---|---|---|---|---|---|---|---|
| kg (kilogram) | — | 1,000 | 1,000,000 | 0.001 | 2.204623 | 35.273962 | 0.15747304 |
| g (gram) | 0.001 | — | 1,000 | 0.000001 | 0.0022046226 | 0.03527396 | 0.000157473 |
| mg (milligram) | 0.000001 | 0.001 | — | 0.000000001 | 0.0000022046 | 0.000035274 | 0.0000001575 |
| t (metric tonne) | 1,000 | 1,000,000 | 1,000,000,000 | — | 2,204.62 | 35,273.96 | 157.473 |
| lb (pound) | 0.45359237 | 453.592 | 453,592.37 | 0.0004535924 | — | 16 | 0.07142857 |
| oz (ounce) | 0.02834952 | 28.349523 | 28,349.52 | 0.0000283495 | 0.0625 | — | 0.0044642857 |
| st (stone) | 6.350293 | 6,350.29 | 6,350,293.18 | 0.0063502932 | 14 | 224 | — |
Conversions by starting unit
kilograms (kg)
kg to gkg to mgkg to tkg to lbkg to ozkg to st
grams (g)
g to kgg to mgg to tg to lbg to ozg to st
milligrams (mg)
mg to kgmg to gmg to tmg to lbmg to ozmg to st
metric tonnes (t)
t to kgt to gt to mgt to lbt to ozt to st
pounds (lb)
lb to kglb to glb to mglb to tlb to ozlb to st
ounces (oz)
oz to kgoz to goz to mgoz to toz to lboz to st
stone (st)
st to kgst to gst to mgst to tst to lbst to oz
Tools for a specific job
The same units, in a tool built around one task. Each one covers only what that job needs, and shows the factors it applied.
Common questions
Is the pound defined exactly?
Yes. Since 1959 the avoirdupois pound has been defined internationally as exactly 0.45359237 kilograms, so kilogram-to-pound conversions are exact by definition, not measured.
Why does UK 'stone' still exist?
Stone (14 pounds) remains the customary body-weight unit in the UK and Ireland. It is exactly 6.35029318 kilograms.
Are ounces here weight or volume?
Weight. The avoirdupois ounce is 28.349523125 grams; fluid ounces measure volume and are a different unit entirely.