Length Converter
Convert between 19 length units instantly. Enter a value, pick your units and get the result with the formula, a full conversion table and worked examples.
10 in in all length units
Updates live as you type. Click a row to set it as the target unit.
| Unit | Symbol | Value |
|---|---|---|
| Nanometre | nm | 254,000,000 |
| Micrometre (micron) | µm | 254,000 |
| Millimetre | mm | 254 |
| Centimetre | cm | 25.4 |
| Decimetre | dm | 2.54 |
| Metre | m | 0.254 |
| Kilometre | km | 0.000254 |
| Mil (thou) | mil | 10,000 |
| Inch | in | 10 |
| Foot | ft | 0.833333 |
| Yard | yd | 0.277778 |
| Mile | mi | 0.000157828 |
| Nautical mile | nmi | 0.000137149 |
| Fathom | ftm | 0.138889 |
| Chain | ch | 0.0126263 |
| Furlong | fur | 0.00126263 |
| Angstrom | Å | 2,540,000,000 |
| Astronomical unit | au | 1.69789 × 10−12 |
| Light year | ly | 2.68478 × 10−17 |
How to Convert Length Units
Length measures the distance between two points. The SI base unit is the metre (m); imperial units such as the inch, foot and mile are defined exactly in metres (1 in = 0.0254 m).
Every unit on this page is stored as a fixed factor relative to one reference unit, the metre (m). Converting is a two step multiply and divide:
- Multiply your value by the factor of the source unit to get the value in m.
- Divide that result by the factor of the target unit.
Inch to Millimetre conversion table
| Inch (in) | Millimetre (mm) |
|---|---|
| 1 in | 25.4 mm |
| 2 in | 50.8 mm |
| 3 in | 76.2 mm |
| 4 in | 101.6 mm |
| 5 in | 127 mm |
| 6 in | 152.4 mm |
| 7 in | 177.8 mm |
| 8 in | 203.2 mm |
| 9 in | 228.6 mm |
| 10 in | 254 mm |
| 15 in | 381 mm |
| 20 in | 508 mm |
| 25 in | 635 mm |
| 30 in | 762 mm |
| 40 in | 1,016 mm |
| 50 in | 1,270 mm |
| 75 in | 1,905 mm |
| 100 in | 2,540 mm |
| 250 in | 6,350 mm |
| 500 in | 12,700 mm |
| 1,000 in | 25,400 mm |
Length Units and Conversion Factors
Value of one unit expressed in m.
| Unit | Symbol | In m |
|---|---|---|
| Nanometre | nm | 1 × 10−9 |
| Micrometre (micron) | µm | 0.000001 |
| Millimetre | mm | 0.001 |
| Centimetre | cm | 0.01 |
| Decimetre | dm | 0.1 |
| Metre | m | 1 |
| Kilometre | km | 1,000 |
| Mil (thou) | mil | 0.0000254 |
| Inch | in | 0.0254 |
| Foot | ft | 0.3048 |
| Yard | yd | 0.9144 |
| Mile | mi | 1,609.344 |
| Nautical mile | nmi | 1,852 |
| Fathom | ftm | 1.8288 |
| Chain | ch | 20.1168 |
| Furlong | fur | 201.168 |
| Angstrom | Å | 1 × 10−10 |
| Astronomical unit | au | 149,597,870,700 |
| Light year | ly | 9.460730473 × 1015 |
Frequently Asked Questions
What is the SI unit of length?
The SI unit of length is the metre (m). Length measures the distance between two points.
How do I convert in to mm?
To convert inch (in) to millimetre (mm), multiply the value in in by 25.4. For example, 1 in = 25.4 mm.
How do I convert ft to metre?
To convert foot (ft) to metre (m), multiply the value in ft by 0.3048. For example, 1 ft = 0.3048 m.
How do I convert mi to km?
To convert mile (mi) to kilometre (km), multiply the value in mi by 1.60934. For example, 1 mi = 1.60934 km.
Can I see a value in every length unit at once?
Yes. Enter a value and choose the source unit; the "all units" table below the converter instantly lists the equivalent in all 19 supported units. Click any row to make it the target unit.
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