--- title: "Length Converter - mm, cm, m, km, in, ft, yd, mi | CanDoYa" description: "Free length and distance converter. Enter a value and convert instantly between millimeters, centimeters, meters, kilometers, inches, feet, yards, miles and more - runs in your browser." url: https://candoya.com/tools/length-converter/ locale: en type: browser-tool --- # Length Converter Category: Converters ## How do you convert between length units? Pick the unit you have, type a number, and pick the unit you want. This length converter turns your value into every metric and imperial unit at once - mm, cm, m, km, inches, feet, yards, miles and nautical miles - using exact conversion factors, instantly and entirely in your browser. Every length unit here is defined by an exact factor to the meter, so the conversions are precise rather than approximate: an inch is exactly 0.0254 meters, a foot is 0.3048 m, a yard is 0.9144 m, a mile is 1609.344 m and a nautical mile is exactly 1852 m. Enter a value, choose your *from* and *to* units, and the big number updates as you type, with a reference table showing the same length in all ten units at once. Use the swap arrows to reverse the direction. Nothing is uploaded - the math happens on the page. ## How to use it 1. **Enter a length** - Type a number in the value field. Decimals are fine - use a dot or a comma, e.g. 5 or 5.5 or 5,5. 2. **Choose the units** - Pick the unit you are converting from next to the number, and the unit you want in the To dropdown. 3. **Read every unit at once** - The big result shows your target unit; the table below shows the same length in all ten units. Use the swap arrows to reverse it, or Copy result to grab the figure. ## Who it's for - **DIY, building and crafts** - convert a measurement from centimeters or millimeters to inches (or the reverse) before cutting, drilling or ordering material. - **Travel and maps** reading a distance in kilometers and wanting it in miles, or a trail sign in miles when you think in kilometers. - **Sports and fitness** converting a run, swim or ride between meters, kilometers, yards and miles. - **Sailing and aviation** working with nautical miles alongside kilometers and statute miles. - **Students and engineers** checking a unit conversion with exact factors instead of a rounded rule of thumb. ## Expert note The imperial units are not rough approximations of the metric ones - since the 1959 international agreement they are DEFINED in metric terms, which is why this converter is exact: 1 inch is precisely 25.4 mm, so a foot is 304.8 mm and a mile is 1,609.344 m. The one unit people mix up is the mile: a statute (land) mile is 1,609.344 m, but a nautical mile is 1,852 m - about 15% longer - because it is tied to one minute of latitude on the Earth, not to feet. If a boat or aircraft speed is in knots, that is nautical miles per hour, so convert distances with the nmi row, not the mi row. ## Frequently asked questions ### Is the length converter free? Yes - it is 100% free, with no sign-up and no limits. Every conversion runs in your browser and nothing you type is uploaded or stored. ### Which length units does it convert? Ten units: micrometers, millimeters, centimeters, meters and kilometers on the metric side, and inches, feet, yards, miles and nautical miles on the imperial and nautical side. You can convert between any two of them. ### How many centimeters are in an inch? Exactly 2.54 centimeters, because an inch is defined as 25.4 millimeters. So 10 inches is 25.4 cm and 1 foot (12 inches) is 30.48 cm. ### How do I convert kilometers to miles? Multiply kilometers by 0.621371 to get miles, since 1 mile is 1.609344 km. So 5 km is about 3.107 miles and 10 km is about 6.214 miles. Enter the value and this tool shows it instantly. ### What is the difference between a mile and a nautical mile? A statute (land) mile is 1,609.344 meters; a nautical mile is 1,852 meters, roughly 15% longer. Nautical miles are used at sea and in the air because one nautical mile equals about one minute of latitude. ### Can I convert very small or very large lengths? Yes. Micrometers handle very small measurements (1 micrometer is a thousandth of a millimeter) and kilometers or miles handle large distances. Extreme results are shown in scientific notation so the number stays readable. ### Does it work with decimals and commas? Yes. You can type a dot or a comma as the decimal mark, so both 5.5 and 5,5 are read as five and a half. Whitespace is ignored. ## Related tools - [Meters to Feet Converter](https://candoya.com/tools/meters-to-feet/) - [Temperature Converter](https://candoya.com/tools/temperature-converter/) --- *Markdown edition of , published for AI agents and other automated readers. Index of key pages: .*