Weight is an everyday term used to describe the quantity of an object. Scientists use the term mass to describe this. (For more information click here).

A scale is a device used to measure weight.

Weight is measured using the same systems used for measuring length. The standard U.S. Customary Unit for measuring weight is the Pound. The standard unit of the Metric System is the kilogram. The tables below show these two systems of measurement.

When To Use Which Unit?

When you measure the weight of a very small object, such as a leaf, the best unit to use is a milligram or fractions of an ounce.

The weight of a larger object, such as an orange, is measured using grams or ounces.

Large objects, such as a person, can be measured using kilograms or pounds.

When measuring even bigger objects, like a hippopotamus, the best units to use are tons or kilograms.

Table of Weight Conversions
U.S. Customary
Metric System