Length measures distance along one dimension. Use consistent units before comparing dimensions or multiplying lengths to calculate areas.
The formula
How to use it
The international inch is exactly 2.54 centimeters. Divide centimeters by 2.54 to obtain inches. A 100 cm length is approximately 39.37007874 inches. A foot contains 12 inches, a yard contains 3 feet, and an international mile contains 5280 feet. Do not apply a length factor directly to area: square the factor when converting squared units.
Related measurement tools
Check the result
Keep intermediate digits until the end, then round to the precision appropriate for the original measurement. Converting to a different unit does not make an imprecise measurement more accurate. Try the linked tool for a reference table and a comparison with related units.
Open converter →Definition references: NIST Guide to the SI and BIPM SI Brochure.