Length Converter: Units, Formulas, and Examples
Convert distances between metric units, inches, feet, yards, miles, and nautical miles.
How to convert length
Converted value = input value × source factor ÷ target factor. Factors express each unit in meters.
Keep the source and target definitions consistent, apply the conversion to the original value, and round the final answer to the precision needed for your calculation.
Understanding length units
The meter is the SI base unit of length. This calculator uses the international foot and mile: 1 foot = 0.3048 meters and 1 mile = 1,609.344 meters. A nautical mile is 1,852 meters.
| Unit | In m |
|---|---|
| Meters (m) | 1 |
| Kilometers (km) | 1,000 |
| Centimeters (cm) | 0.01 |
| Millimeters (mm) | 0.001 |
| Micrometers (µm) | 0.000001 |
| Nanometers (nm) | 0.000000001 |
| Inches (in) | 0.0254 |
| Feet (ft) | 0.3048 |
| Yards (yd) | 0.9144 |
| Miles (mi) | 1,609.344 |
| Nautical miles (nmi) | 1,852 |
Worked length examples
1 meter is approximately 3.280839895 feet. 12 inches = 1 foot; 5 kilometers = 5,000 meters.
Frequently asked questions
Which definitions should I use?
These feet and miles use international definitions. Historical US survey units are different and are not included.
Why do displayed results sometimes differ slightly?
Intermediate arithmetic uses browser floating-point numbers. Display rounding and the precision of an original measurement can affect the last digits. The unit conversion does not improve the accuracy of a measured value.
Does converting back recover the original value?
Using the unrounded result normally recovers the original quantity within floating-point precision. Copying a rounded number can introduce a small difference.
How are the unit definitions documented?
For physical unit definitions and conversion factors, see the NIST conversion reference.