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Weight converter (mass)

Kilograms, pounds, ounces, stone, grams, tonnes, short and long tons, troy ounces and carats, converted both ways.

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Weight shows up in different units depending on who is asking: airlines quote checked-bag limits as 23 kg (50.7 lb), UK scales and doctors still use stone (14 lb), recipes from the US use ounces, gold is priced per troy ounce and gemstones per carat. This converter handles all of them from one input and shows the factor for the pair you pick.

The pound has been defined as exactly 0.45359237 kg since the 1959 international yard and pound agreement, so kilogram-pound conversions are exact: 1 kg = 2.20462262 lb. An avoirdupois ounce is 1/16 lb (28.349523125 g). The troy ounce used for precious metals is heavier, exactly 31.1034768 g, and the metric carat is exactly 200 mg. A US short ton is 2000 lb (907.18474 kg) and a UK long ton 2240 lb (1016.05 kg); the metric tonne is 1000 kg.

Scientifically these are units of mass; "weight" in everyday use means the same thing, and the numbers are identical on any scale calibrated on Earth.

How to use it

  1. Choose the unit you have (for example kilogram) and the unit you need (for example pound).
  2. Type the value in either box; the other updates as you type.
  3. Set the number of decimals, or read other values from the table below the converter.

Frequently asked questions

How many pounds are in a kilogram?

1 kg = 2.20462262 lb, because 1 lb is defined as exactly 0.45359237 kg. For a quick estimate, double the kilograms and add 10%: 70 kg → 154 lb (exact 154.32).

How do I convert stone to kilograms?

One stone is 14 lb, which is exactly 6.35029318 kg. A person weighing 11 st 4 lb weighs 158 lb, or 71.67 kg. Enter the stone value with decimals (11.2857 st) or convert the pounds directly.

Is a troy ounce the same as a regular ounce?

No. Precious metals use the troy ounce, 31.1034768 g, which is about 9.7% heavier than the avoirdupois ounce (28.3495 g) used for food and parcels. Gold and silver prices are always per troy ounce.

What is the difference between a ton and a tonne?

A tonne (metric ton) is 1000 kg. A US short ton is 2000 lb (907.18 kg) and a UK long ton 2240 lb (1016.05 kg). Shipping and engineering documents outside the US usually mean the metric tonne.

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