Length Converter
Convert a length into every metric, US customary and nautical unit at once.
Length units and definitions
The size of each unit is listed below. The metric units are defined by SI prefixes. The inch, foot, yard and mile are the international units (exactly 0.0254 m per inch). The nautical mile is exactly 1,852 m.
| Unit | Size of one unit | Definition and source |
|---|---|---|
| Metric (SI) | ||
| km (kilometer) | 1,000 m | Metric (SI) unit |
| m (meter) | 1 m | Metric (SI) unit |
| cm (centimeter) | 0.01 m | Metric (SI) unit |
| mm (millimeter) | 0.001 m | Metric (SI) unit |
| μm (micrometer) | 0.000001 m | Metric (SI) unit |
| US customary, imperial and nautical | ||
| inch (in) | 0.0254 m | 1/36 of a yard. NIST SP 811 |
| foot (ft) | 0.3048 m | 1/3 of a yard (the international foot, not the U.S. survey foot). NIST SP 811 |
| yard (yd) | 0.9144 m | 3 feet. NIST SP 811 |
| mile (mi) | 1,609.344 m | 1,760 yards (the international mile). NIST SP 811 |
| nautical mile (nmi) | 1,852 m | Exactly 1,852 m. NIST SP 811 |
The calculator first converts your length to meters, then divides by the size of each unit. Calculations use exact fractions, and the only rounding is the one applied when a value is displayed.
Examples
- 1 mile = 1.609344 km = 1,760 yards = 5,280 feet
- 1 inch = 2.54 cm = 25.4 mm (exact)
- 1 foot = 0.3048 m = 12 inches
- 1 nautical mile = 1.852 km (exact)
- 1 m ≈ 3.28084 ft
Notes
- You can enter decimals (up to 12 digits before the decimal point and 6 decimal places). Thousands separators such as 1,234.5 are accepted; use a period as the decimal separator.
- The foot used here is the international foot (0.3048 m). The U.S. survey foot is a slightly different unit and is not included.
- The mile is the international (statute) mile of 1,609.344 m. The nautical mile (1,852 m) is a different unit.
- The metric spelling used on this page is the American one (meter, kilometer).
Sources
The definitions on this page come from the sources below. Some values are the exact values this tool uses (for example, the pound as exactly 0.45359237 kg), and the sources may list them rounded; the notes in the table say which values are used by this tool.
Frequently asked questions
How many kilometers are in a mile?
1 mile is 1.609344 km. It is also 1,609.344 m, 5,280 feet and 1,760 yards.
How many centimeters are in an inch?
2.54 cm (25.4 mm). This is a defined value, so there is no rounding error.
What is the difference between a nautical mile and a mile?
A nautical mile is exactly 1,852 m and a mile is 1,609.344 m. They are different units. Nautical miles are used for sea and air navigation.
How do I convert feet to meters?
Multiply the number of feet by 0.3048 to get meters, or divide meters by 0.3048 to get feet. In this tool, just pick the units.