Type a value, choose the units and get an instant answer. The table below the converter shows the same value in every length unit, and all factors use exact or internationally standard definitions.
How to convert length units
- Enter the value.
- Pick the unit to convert from and to (⇄ swaps them).
- Read the result, formula and the table of all units.
Length units
| Unit | Symbol | About |
|---|---|---|
| Millimeter | mm | One thousandth of a metre. Used for small measurements, rainfall and engineering drawings. |
| Centimeter | cm | One hundredth of a metre. Used for body height, clothing and everyday objects in most of the world. |
| Meter | m | The SI base unit of length, defined by the distance light travels in 1/299,792,458 of a second. |
| Kilometer | km | One thousand metres. The standard unit for road distances outside the US and UK. |
| Inch | in | Exactly 2.54 cm since 1959. Used for screens, tyres, pipes and height in the US, UK, Pakistan and India. |
| Foot | ft | Exactly 12 inches or 30.48 cm. Used for height, room sizes and property in the US, UK and South Asia. |
| Yard | yd | Exactly 3 feet or 91.44 cm. Used for fabric, sports fields and (as “gaz”) land and cloth in South Asia. |
| Mile | mi | The statute mile: 5,280 feet or 1.609344 km. Used for road distances in the US and UK. |
| Nautical mile | nmi | Exactly 1,852 m, based on one minute of latitude. Used at sea and in aviation. |
| Micrometer | µm | One millionth of a metre (a micron). Used for cells, fibres and manufacturing tolerances. |
| Nanometer | nm | One billionth of a metre. Used for light wavelengths and semiconductor processes. |
| Light-year | ly | The distance light travels in one Julian year, about 9.46 trillion km. |
Popular length conversions
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Frequently asked questions
How accurate is the length converter?
It uses exact definitions where they exist and shows up to 10 significant figures, more than enough for everyday, school and engineering use.
Updated October 2026 · Built and tested by Sharjeel Tahir · How our tools are tested