Length Converter
Convert between metric and imperial lengths with NIST-exact factors — from nanometers to nautical miles, right in your browser.
| Reference | Exact value |
|---|---|
| 1 inch | 2.54 cm |
| 1 foot | 0.3048 m |
| 1 yard | 0.9144 m |
| 1 mile | 1609.344 m |
| 1 nautical mile | 1852 m |
How to use
- Type a value and pick the units to convert from and to.
- The result updates as you type — no button needed.
- Hit ⇅ to swap the two units and invert the conversion.
Frequently asked questions
Which length units are supported?
Eleven: meter, kilometer, centimeter, millimeter, micrometer, nanometer, mile, yard, foot, inch and nautical mile. Metric factors are powers of ten; imperial ones use the international definitions agreed in 1959.
How exact are the conversions?
The table uses NIST exact values: 1 inch = 0.0254 m, 1 foot = 0.3048 m, 1 mile = 1609.344 m, 1 yard = 0.9144 m and 1 nautical mile = 1852 m — no approximations are involved. Results are rounded to 6 significant digits for display only.
What is the difference between a mile and a nautical mile?
A statute mile (1609.344 m) comes from Roman marching distances and is used on land. A nautical mile (1852 m) equals one minute of latitude and is the standard unit in aviation and marine navigation.
Why does my result show a very long or exponential number?
Converting between extremely different scales (nanometers to miles) can produce 15-digit values. The tool switches to exponential notation below one millionth to keep results readable — the underlying math stays exact.
Does the swap button change my value?
No — it only swaps the from/to units so you can invert the conversion instantly. Your typed number stays the same, and the result recalculates for the reversed direction.