Lawn mowers can receive a lot of abuse during the summer mowing season. Some parts on lawn mowers will not last for the lifetime of the mower. Belts in the lawn mower may either be in the motor or turn the mower blade. Belts tend to stretch and become loose or break after wearing out from extended use. To replace the lawn mower belt, you will need to measure the belt's length and width in order to find a proper replacement.
Lay the belt flat on a hard surface.
Measure the belt by wrapping the cloth tape measure around the belt. For broken belts, simply measure the total length of the belt.
Hold the cloth tape measure against the length or width of the belt depending upon which measurement you need.