Length Converter
Convert metric, US customary, nautical, and astronomical length units with formulas and copy-ready output.
Enter a distance or length, choose the source and target units, and generate a copy-ready conversion. The calculation stays in your browser and uses exact SI relationships for the supported units where standards define them.
Use a non-negative number. Commas as thousands separators and scientific notation are accepted.
How it works
The converter first expresses your input in meters, then divides by the target unit length. Metric units use powers of ten around the SI metre. Inch, foot, yard, and international mile use the exact international inch relationship of 1 inch = 0.0254 meters.
Nautical miles use the international value of 1,852 meters. Astronomical units and light-years are included for scale comparisons and use standard reference values; results for very large distances are formatted with scientific notation when that is easier to read.
Use this tool for engineering notes, travel estimates, mapping checks, classroom examples, and quick unit tables. It does not include every historical, survey, or trade-specific length unit, so use a domain source when a specialized unit definition is required.
