Length Converter
Convert a length between millimetres, centimetres, metres, kilometres, inches, feet, yards and miles. Converts instantly in your browser.
Also searched as: cm to inches · feet to meters · inches to cm · km to miles
Updated November 6, 2026
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How to use it
- 1
Enter a value
Type the length you want to convert.
- 2
Pick the units
Choose what to convert from and to.
- 3
Read the result
The answer updates as you type.
Questions about length converter
How accurate is it?
It uses exact conversion factors, so results are accurate to several decimal places.
Does it do both metric and imperial?
Yes, you can convert in either direction between metric and imperial units.
Is anything uploaded?
No, the conversion runs on your device.
Metric and imperial lengths side by side
The metric system builds every length from the metre, so moving between millimetres, centimetres, metres and kilometres only shifts the decimal point. Imperial and US customary lengths have no common base: 12 inches make a foot, 3 feet make a yard and 1,760 yards make a mile. This converter joins the two systems through the metre, using the exact definitions 1 inch = 2.54 cm, 1 foot = 0.3048 m, 1 yard = 0.9144 m and 1 mile = 1,609.344 m.
The table shows what one of each unit equals in metres, feet and inches, so you can read the common conversions without typing anything.
| One of… | Metres (m) | Feet (ft) | Inches (in) |
|---|---|---|---|
| Millimetres (mm) | 0.001 | 0.003281 | 0.03937 |
| Centimetres (cm) | 0.01 | 0.03281 | 0.3937 |
| Metres (m) | 1 | 3.281 | 39.37 |
| Kilometres (km) | 1,000 | 3,281 | 39,370 |
| Inches (in) | 0.0254 | 0.08333 | 1 |
| Feet (ft) | 0.3048 | 1 | 12 |
| Yards (yd) | 0.9144 | 3 | 36 |
| Miles (mi) | 1,609 | 5,280 | 63,360 |
Worked examples
To convert 5 feet 10 inches to centimetres, convert each part and add them: 5 ft is 152.4 cm and 10 in is 25.4 cm, so the height is 177.8 cm. Whenever a length has two parts, convert each part on its own and add the results. Round only at the end, to the precision your task needs.
A marathon is 42.195 km, which is about 26.22 miles. A mile is about 1.609 km, so for a quick estimate multiply miles by 1.6 to get kilometres.