Weight & Mass Converter

How to convert weight and mass units

All weight conversions are based on the kilogram, the SI base unit of mass: multiply by the ratio of the two units. The pound is defined as exactly 0.45359237 kg, giving pounds = kilograms × 2.20462 and kilograms = pounds × 0.45359237. Within the imperial system the steps are whole numbers - 1 pound is 16 ounces and 1 stone is 14 pounds. (Strictly the tool converts mass; "weight" is the everyday word for it.)

Worked example

To convert 70 kilograms to pounds, multiply by 2.20462: 70 × 2.20462 = 154.32 lb. A 5-pound bag is 5 × 16 = 80 oz, and 250 grams is 250 ÷ 28.3495 = 8.82 oz.

How many pounds are in a kilogram?

One kilogram equals 2.204622622 pounds. One pound equals exactly 0.45359237 kilograms (16 ounces), one ounce equals 28.3495 grams, one stone equals 6.35029318 kilograms (14 pounds), and one metric tonne equals 1,000 kilograms. The pound and ounce are fixed by the international avoirdupois definitions; the kilogram is an exact SI base unit.

When you'll use a weight converter

Weight and mass conversion shows up in cooking and baking (grams to ounces), shipping and luggage limits (kilograms to pounds), body-weight tracking (kilograms, pounds and stones), and lab or jewellery work (milligrams, carats, grains). The table above lists your value in all 10 supported units at once.

Frequently asked questions

How many grains are in a pound?

There are exactly 7,000 grains in one avoirdupois pound. One grain equals 0.06479891 grams, and it is still used for bullets, gunpowder and pharmacy weights.

What is a carat in grams?

One metric carat equals exactly 0.2 grams, which is 200 milligrams. Carats measure gemstones and pearls, so a 5-carat diamond weighs 1 gram.

How many kilograms are in a US short ton?

One US short ton equals 907.18474 kilograms, which is 2,000 pounds. It is the everyday ton in the United States and is lighter than the metric tonne of 1,000 kilograms.

Is a metric tonne the same as a US ton?

No. A metric tonne is 1,000 kilograms, while a US short ton is 907.18474 kilograms, so the tonne is about 10 percent heavier. Always check which ton a quantity refers to before converting.

How many milligrams are in a gram?

One gram contains 1,000 milligrams, and one kilogram contains 1,000,000 milligrams. Milligrams are used for medication doses, vitamins and laboratory measurements.

What is a stone in weight?

A stone is a British imperial unit equal to 14 pounds, or about 6.35 kilograms. It is mainly used in the United Kingdom and Ireland to state body weight.