Length is a measurement of linear distance. The metric system uses millimeters (mm), centimeters (cm), meters (m) and kilometers (km). The Imperial system uses inches and fractions (“), feet (‘) and miles (mi). You will use length measurements frequently when replacing and repairing fasteners, determining wheelbase, shaft sizes - in short, any time you would use a ruler.
| Length conversions | |
| 1 km = 1000m | 1 mi = 1.61 km |
| 1 km = 0.62 mi | 1 ft = 0.304 m |
| 1 cm = 0.39” | 1” = 2.54 cm |
| 1 mm = 0.039” | ½” = 12.7 mm |
