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Weight Converter

Convert weight between kilograms, grams, pounds, ounces, stones and tonnes, with US and UK tons listed separately because they differ. One pound is exactly 0.45359237 kg, so a kilogram is about 2.20462 pounds. For stones, multiply by 14 and add the pounds: 11 stone 4 pounds is about 71.67 kg.

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Updated

How to use the Weight Converter

  1. 1Type a value into any box — every other unit updates as you type.
  2. 2Use the swap button to flip the two headline units.
  3. 3Copy any result with the button beside it.
  4. 4Adjust the decimal places if you need more or less precision.

How it works

Every unit here is defined against the kilogram. The avoirdupois pound — the ordinary pound used for everyday weight — has been defined as exactly 0.45359237 kilograms since 1959, which makes ounces, stones and hundredweights exact as well.

Two traps are worth knowing about. A US ton is 2,000 pounds while a UK long ton is 2,240, and a metric tonne is 1,000 kg — three different things that all get called a ton, so they are listed separately here. Strictly, these are units of mass; weight is a force. In everyday use the distinction rarely matters, but it is why a kilogram is the same on the Moon while your weight is not.

Conversion works by taking your value to a single base unit and then out again, so every pair of units is consistent with every other. Values are calculated at full double precision and only rounded for display, which means round-tripping a number through two conversions returns what you started with.

The formula

value in target = (value × factor of source) ÷ factor of target
factor
how many kilograms one of that unit represents
kilogram
the base unit every factor is defined against

1 lb = 0.45359237 kg exactly; 1 stone = 14 lb; 1 oz = 1/16 lb.

Worked example

Converting 11 stone 4 pounds to kilograms

  1. 11 × 14 + 4 = 158 pounds
  2. 158 × 0.45359237 = 71.67

Result: About 71.67 kilograms.

Tips and common mistakes

  • In the UK, body weight is often given in stones and pounds; one stone is 14 pounds.
  • Check which ton is meant — metric, US short or UK long — before converting a shipping or freight weight.
  • Precious metals are weighed in troy ounces, which are heavier than ordinary ounces.
  • For cooking, weighing ingredients is more accurate than converting cups.

Frequently asked questions

How many pounds are in a kilogram?
About 2.20462. Going the other way, one pound is exactly 0.45359237 kg.
How do I convert stones and pounds to kilograms?
Multiply the stones by 14, add the pounds, then multiply the total by 0.45359237.
Which ton is which?
A metric tonne is 1,000 kg, a US short ton is 2,000 lb (907.18 kg), and a UK long ton is 2,240 lb (1,016.05 kg). All three are listed separately.
How accurate are these conversions?
Factors are defined against the kilogram; the pound is exactly 0.45359237 kg by international agreement. All arithmetic is done at full precision and rounded only when displayed, so results are exact to the digits shown.
How many ounces are in a pound?
16. One ounce is about 28.35 grams.
How many kilograms is 10 stone?
About 63.5 kg: 10 stone is 140 pounds, and 140 × 0.45359237 = 63.50.
Is a troy ounce the same as an ordinary ounce?
No. A troy ounce, used for gold and silver, is about 31.10 grams. The ordinary avoirdupois ounce used for food and parcels is about 28.35 grams.
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