A tool for identifying a correct belt for a system of pulleys from a plurality of prefabricated belts having different lengths is disclosed. The tool may include a belt track attached to a first end portion of a measurement belt. The measurement belt may be wrapped around the system of pulleys. An opposed second end portion of the measurement belt may be disposed adjacent to the belt track which may include a reference indicator. The reference indicator will be aligned to one of a plurality of measurement markings on the second end portion which indicates the correct belt to order from among the plurality of prefabricated belts.