Tables showing the SI equivalents of metric units and some older units commonly used, such as
Millimetres (mm), Centimetres (cm), Decimetres (dm), Metres (m), Kilometres (km), Inches (in), Feet (ft), Yards (yd), Miles (mi), Nautical miles (NM) and Mils (mil)
Units of Length Table
| Unit | SI equivalent | Inverse |
| 1 mm (millimetre) | equals 1 x 10-3 m | 1 m = 1000 mm |
| 1 cm (centimetre) | equals 1 x 10-2 | 1 m = 100 cm |
| 1 m (metre) | equals 1 m | 1 m = 1 m |
| 1 km (kilometre) | equals 1000 m | 1 m = 0.001 km |
| 1 in (inch) | equals 2.540 x 10-2 m | 1 m = 39.37 in |
| 1 ft (foot) | equals 0.3048 m | 1 m = 3.281 ft |
| 1 yd (yard) | equals 0.9144 m | 1 m = 1.094 yd |
| 1 mi (mile) | equals 1.609 x 103 m | 1 m = 6.214 x 10-4 mi |
| 1 NM (nautical mile) | equals 1852 m | 1 m = 5.399568 x 10-4 Nm |
| 1 mil (Mil) | equals 2.54 x 10-5 m | 1 m = 39370.078740157 mil |
Length Table
| Unit | SI symbol | Conversion |
| kilometre | km | 1km = 1000 m |
| metre | m | 1 m = 10 dm = 100 cm = 1000 mm |
| decimetre | dm | 1 dm = 10 cm = 100 mm |
| centimetre | cm | 1 cm = 10 mm |
| millimetre | mm | |