Length converter
Convert one length into 16 metric, imperial and Chinese units at once
Pick the units at both ends to see the result. The common conversions row switches to pairs such as inches to centimetres in one click.
This affects display only. Conversion always uses full precision.
| Unit | Symbol | Result |
|---|---|---|
| Kilometre | km | |
| Metre | m | |
| Decimetre | dm | |
| Centimetre | cm | |
| Millimetre | mm | |
| Micrometre | μm | |
| Nanometre | nm | |
| Mile | mi | |
| Nautical mile | nmi | |
| Yard | yd | |
| Foot | ft | |
| Inch | in | |
| Li (Chinese mile) | 里 | |
| Zhang | 丈 | |
| Chi (Chinese foot) | 尺 | |
| Cun (Chinese inch) | 寸 |
Example
Input
1 km
Example result
m 1000 mi 0.621371192237 ft 3280.83989501 in 39370.0787402
The table lists all 16 units at once; four rows are excerpted here.
Technical details & limits
Factors are applied in double-precision floating point. Imperial units use the 1959 international yard and pound definitions, with one inch as exactly 0.0254 metre; Chinese units use one chi as 1/3 metre. The displayed digits are adjustable, but the arithmetic always runs at full precision with no intermediate rounding.
About this tool
Enter a value, pick the unit it is written in, and the page lists the result in every other length unit: metric from kilometre to nanometre, imperial mile, nautical mile, yard, foot and inch, plus the Chinese li, zhang, chi and cun. The factors are fixed definitions and the arithmetic runs in your browser.
Use cases
- Turn inch dimensions on a drawing into millimetres.
- Cross-check miles and kilometres in a run or ride log.
- Convert traditional chi and cun measurements into centimetres.
How to use
- Type a number. Decimals and scientific notation such as 1.5e3 are accepted.
- Pick the unit the value is in and the unit you want it in. The ⇄ button swaps the two.
- The summary line gives the target unit; the table below lists every metric, imperial and Chinese length unit at the same time.
- Adjust the significant digits for a shorter or longer number. The conversion itself always runs at full precision.
Notes
Li, zhang, chi and cun use the current conversion of one chi to 1/3 metre. Units with the same names in historical sources had different lengths, so do not apply these figures to them.
FAQ
- How many centimeters are in one inch?
- 1 inch equals 2.54 centimeters, using the international inch definition implemented by this tool. The corresponding value in meters is 0.0254. You can view other length units after entering the amount and choose a suitable display precision. Display rounding affects the shown digits rather than rounding every intermediate conversion step, so use the original input when comparing results that appear different only in their final decimal places.
- How do kilometers, meters, and miles differ in conversion?
- Kilometers and meters use a decimal relationship, while miles use the international mile definition. 1 kilometer equals 1000 meters, and 1 mile equals 1609.344 meters. Check the original unit before comparing maps, distances, or activity records. A value reported in miles is not interchangeable with the same numeric value in kilometers, and changing the display precision does not change the conversion factor connecting those units.
- How many meters are in a Chinese chi and an international foot?
- A Chinese market chi and an international foot are different units with different conversion factors. This tool treats 1 chi as 1/3 meter and 1 foot as 0.3048 meter. Select the intended unit explicitly when reading furniture dimensions or technical records. A translated label such as foot can hide the distinction, so confirm the source convention before treating a converted measurement as the intended physical length.
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