About the Length Converter
Length Converter changes a distance between metric and imperial units: millimetres, centimetres, metres, kilometres, inches, feet, yards, miles, nautical miles and micrometres. Type one number, choose its unit, and every other unit shows at once. It uses the exact international definitions, so 1 inch is exactly 25.4 mm and 1 mile exactly 1,609.344 m. It is useful for travel distances, room and furniture sizes, running and cycling routes, school work and any project that mixes metric and imperial measurements.
Updated October 2026
How to use the Length Converter
- 1Type the a length or distance you want to convert.
- 2Choose the unit it is in from the From unit list.
- 3Read the result in every other unit straight away.
- 4Press Copy to keep the answer, or change the number to try another.
When you need a a length or distance converter
Length Converter changes a distance between metric and imperial units: millimetres, centimetres, metres, kilometres, inches, feet, yards, miles, nautical miles and micrometres. Length is the easiest quantity to get wrong when you move between systems, because half the world uses metres and the other half uses feet and miles. Having every unit on one screen means you can check a recipe for a bookshelf, a race distance or a flight route without searching for a separate converter each time.
Units and what they mean
The metre is defined from the speed of light, and the inch, foot, yard and mile are defined as exact fractions of a metre. That is why this page can give exact answers, such as 1 yard = 0.9144 m. The old US survey foot is slightly different (by about 2 parts per million) and is no longer used for new work.
- Millimetre, centimetre, metre, kilometre: the metric ladder, each 10, 100 or 1,000 times the last
- Inch, foot, yard, mile: the imperial and US units, 12 in per ft, 3 ft per yd, 5,280 ft per mi
- Nautical mile: 1,852 m, used at sea and in the air (one minute of latitude)
- Micrometre (micron): a millionth of a metre, used for fibres and fine tolerances
Tips for accurate results
For building and craft projects, convert once, write the result down and measure again in the unit your tape shows. Mixing units inside one calculation is the usual source of errors, so convert every measurement to the same unit before you add or multiply.
Round only at the end of a calculation. If you convert and then convert again, keep the full number in between so small errors do not add up.
Related conversions
For a quick mental check, 1 inch is about 2.5 cm, 1 foot about 30 cm, 1 yard slightly less than a metre and 1 mile about 1.6 km. Related tools: Weight Converter, Area Converter, Speed Converter, Unit Converter and CM to Feet and Inches Converter.
Features
- 10 units in one list
- Every result shown at once
- Exact factors, no rounding until you read it
- Works with decimals and negative-free values
- Copy button for the answer
- Calculated in your browser, so nothing is uploaded.
Frequently asked questions
How do I convert a length or distance?
Type the number, pick the unit you start with and read the answer in every other unit below. Each unit is stored as an exact factor of one base unit, so a result is the number times its factor divided by the target unit's factor.
How many centimetres are in an inch?
Exactly 2.54 centimetres. That is the definition: 1 inch = 25.4 millimetres.
How many feet are in a mile?
5,280 feet. A mile is 1,760 yards, and a yard is 3 feet.
What is a nautical mile?
1,852 metres. It is about one minute of latitude, which is why ships and aircraft use it.
Is the result exact?
The factors used are the official or standard definitions, so the maths is exact. The page rounds what it shows to about 10 significant digits so numbers stay readable.
Does it work on my phone?
Yes. The page is built for small screens, with large inputs and a list of units you can scroll.
Is anything sent to a server?
No. The conversion is plain arithmetic in your browser, so nothing you type leaves your device.