The basic unit for length in the metric system of measurement is the metre (m).
For measuring the lengths of short distances and objects, rulers can be used, using suitable units from the table below.
The commonly used units are millimetres, centimetres, metres and kilometres.
Converting between Units
To convert between the units shown in bold in the first column and the units in the second column, multiply or divide by the factors indicated in the third column.
1. To change 8 cm into mm − multiply by 10.
2. To change 500 m into km − divide by 1000