Length Converter
Convert between metric and imperial length units instantly — millimeters, centimeters, meters, kilometers, inches, feet, yards, and miles.
About Length Converter
Our free Length Converter makes it easy to convert between metric and imperial length units. Whether you're working on a construction project, studying science, traveling internationally, or simply need to convert measurements, this tool provides instant and accurate results.
The converter supports all common length units: millimeters (mm), centimeters (cm), meters (m), and kilometers (km) in the metric system, plus inches (in), feet (ft), yards (yd), and miles (mi) in the imperial system. Simply enter your value, select the source and target units, and get your conversion instantly.
The tool also displays common conversions for your entered value, making it easy to see your measurement in multiple units at once. All conversions are based on internationally accepted standards: 1 inch = 25.4 mm exactly, 1 foot = 0.3048 m, 1 yard = 0.9144 m, and 1 mile = 1.609344 km.
Frequently Asked Questions
Q How many centimeters are in an inch?
There are exactly 2.54 centimeters in one inch. This conversion factor is defined by international agreement and is used as the basis for all metric-imperial length conversions. To convert inches to centimeters, multiply by 2.54. To convert centimeters to inches, divide by 2.54.
Q What is the difference between metric and imperial units?
The metric system (used worldwide) is based on powers of 10: 10mm = 1cm, 100cm = 1m, 1000m = 1km. The imperial system (used primarily in the US and UK) has irregular relationships: 12 inches = 1 foot, 3 feet = 1 yard, 1760 yards = 1 mile. The metric system is simpler for calculations, but imperial units remain common in everyday use in some countries.
Q How many kilometers are in a mile?
One mile equals approximately 1.609344 kilometers. For quick mental estimates, you can use 1.6 km per mile. Conversely, one kilometer equals approximately 0.621371 miles. A handy trick: 5 miles is roughly 8 kilometers, and 10 kilometers is roughly 6.2 miles.