Weight Converter

How to convert weight units

Enter a number, pick the unit you have and the unit you want, and the answer appears immediately along with every other mass unit in the table. Nothing leaves your browser, so it also works with the network off.

All seven units map to a single base, the kilogram, using exact factors. That keeps kg to lb, g to oz and kg to stone mutually consistent instead of each pair having its own rounding.

• Type the mass in the Value box, for example 70.
• Select the unit it is in from the From list, for example Kilogram (kg).
• Select the unit you want from the To list, for example Pound (lb).
• Read the result, or use the table to see grams, ounces and stone at the same time.
• Use Swap units to reverse the direction, and Copy result to take the number away.

Which ounce, which ton, which pound

Three of these unit names are ambiguous outside this page, and each ambiguity has a cost. The ounce here is the avoirdupois ounce, 28.349523125 g, used for food, post, and shipping. The troy ounce that prices gold and silver is 31.1034768 g, about 9.7 percent heavier, so treating a bullion weight as an avoirdupois ounce understates it by roughly a tenth.

The ton is worse, because three of them are in circulation. This converter has only the metric ton of 1,000 kg, which is 2204.62262185 lb. The US short ton is 2,000 lb (907.18474 kg) and the UK long ton is 2,240 lb (1016.0469088 kg). A shipping document that just says "tons" is ambiguous by up to ten percent, and the only fix is to ask.

The pound at least is unambiguous in commerce: the international avoirdupois pound has been exactly 0.45359237 kg since the 1959 agreement between the English-speaking standards bodies. The troy pound still exists for precious metals at 373.2417216 g and is not in this list.

• Avoirdupois ounce 28.349523125 g (here) vs troy ounce 31.1034768 g (not here).
• Metric ton 1,000 kg (here) vs short ton 907.18474 kg vs long ton 1016.0469088 kg.
• Stone is exactly 14 lb, or 6.35029318 kg, and is used almost only in the UK and Ireland.

Body weight, stone, and compound readings

Body weight is the most searched use of this converter, and the three regions involved each use a different unit: kilograms across most of the world, pounds in the United States, and stone-and-pounds in the UK and Ireland. Because a stone is 14 lb, a UK reading is compound rather than decimal: 11 st 4 lb, not 11.29 st.

This converter takes a single number, so a compound reading has to be flattened first. Multiply the stone by 14, add the pounds, and enter the total: 11 st 4 lb becomes 158 lb, which reads as 71.66759446 kg. Going the other way, the decimal part of a stone result is a fraction of fourteen pounds, so 11.0231131092 st is 11 st and about 0.32 lb.