For most weight conversions you can use our multi-unit converter to select the unit to convert and the amount to be converted by selecting the unit from the drop down and entering the amount in the box below. Change the weight system by selecting from the top selecters.

Select Converter From Those Below

Weight conversions between various different systems, metric, imperial, avoirdupois and troy, can be selected from the links below

Metric to Metric	Metric to Imperial	Metric to Troy
Imperial to Metric	Imperial to Imperial	Imperial to Troy
Troy to Metric	Troy to Imperial	Troy to Troy

Metric Weight Units

The base unit of weight in the metric system is the kilogram, all other weight units used in the metric system are based on the kilogram. The kilogram is part of the MKS system of units (metre, kilogram second) which is the basis of the SI system of units. Technically the kilogram is a unit of mass, but in common terminology this is called weight.

Imperial Weight Units

Commonly called the Imperial system the formal name for this system of weights is the Avoirdupois system. Imperial weights are in everyday use in the US and the UK, they are also used in some places in Canada where the metric system is now fully in formal use. There are some differences between the UK Imperial system and the US customary system which occurred after US independence, stemming from the definition of a hundredweight as 100 lbs in the US whereas in the UK a hundredweight is 112 lbs.

Troy Weight Units

Troy weights are mainly used to measure the weights of gemstones, precious metals and gunpowder (grains). The grain is a common unit between the Avoirdupois (Imperial) system and the troy system, whereas other troy units are distinct from their Imperial counterparts.