Metric and imperial length conversions
Length Converter
Convert millimetres, centimetres, metres, kilometres, inches, feet, yards and miles instantly with our free online length converter. No signup required.
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How to Convert Length Units
Length conversion is one of the most common measurement tasks, whether you are following a DIY plan, ordering materials, sewing, or comparing product dimensions across countries that use different systems. The metric system (millimetres, centimetres, metres, kilometres) is used almost everywhere in the world, while imperial units (inches, feet, yards, miles) remain standard in the United States and are still widely used in the UK for many everyday purposes.
Key Length Conversion Formulas
1 inch = 2.54 cm (exact definition)
1 foot = 30.48 cm, so metres = feet × 0.3048
1 yard = 0.9144 m
1 mile = 1.60934 km
To convert from any unit to any other, the calculator above uses standard SI factors: every unit is expressed relative to the metre, then converted to your target unit. For example, to convert inches to centimetres, multiply the number of inches by 2.54.
Common Length Conversions
| Unit | Equals | Real-world reference |
|---|---|---|
| 1 inch (in) | 2.54 cm | Width of a standard credit card |
| 1 foot (ft) | 30.48 cm | Roughly the length of a football boot |
| 1 yard (yd) | 0.9144 m | Distance from nose to fingertips on an outstretched arm |
| 1 metre (m) | 3.281 ft | Just over three feet |
| 1 kilometre (km) | 0.6214 miles | A 10 km run is about 6.2 miles |
| 1 mile (mi) | 1.609 km | 16 city blocks in Manhattan |
When Do You Need a Length Converter?
- Home improvement: Converting furniture or room dimensions between metric and imperial when following international plans
- Fashion and tailoring: Fabric is sold by the metre in Europe and by the yard in the US; patterns mix inches and centimetres
- Travel and fitness: Understanding distances in kilometres versus miles when running, cycling or driving abroad
- Shipping and logistics: Parcel size limits are quoted in different units depending on the carrier and country
- Construction: Building materials are specified in millimetres and metres on most projects, but imperial sizes still appear on tools and fittings
Metric vs Imperial: A Quick History
The metric system was developed in France in the 1790s and is now the official system of measurement in every country except the United States, Liberia and Myanmar. The metre was originally defined as one ten-millionth of the distance from the equator to the North Pole. Today it is defined by the speed of light, which makes it completely universal and precise. Imperial units grew from older English units based on human body parts: the inch was originally the width of a thumb, and the foot the length of a man's foot. That is why exact conversions matter: our calculator uses the modern exact definitions, not the historical approximations.
Frequently Asked Questions
How many centimetres are in an inch?
1 inch is exactly 2.54 centimetres. To convert inches to centimetres, multiply by 2.54. To go the other way, divide by 2.54. Our length converter does this instantly for any value.
How do I convert feet to metres?
Multiply the number of feet by 0.3048 to get metres. For example, 6 feet × 0.3048 = 1.829 metres (about 183 cm). This is the exact conversion used by the calculator.
How many metres are in a mile?
One mile is exactly 1,609.344 metres, which is 1.609 km. This is why a 5 km run is roughly 3.1 miles and a marathon (42.195 km) is 26.2 miles.
Is a yard longer than a metre?
No. One yard is 0.9144 metres, so a metre is about 9.4% longer than a yard. One metre equals 1.094 yards. In American football, the field is 100 yards (91.44 metres) long.
Does the length converter work offline?
Yes. All conversions run locally in your browser using exact SI conversion factors, so the page works offline once loaded and never sends your data to a server.
What is the difference between a nautical mile and a statute mile?
A statute (land) mile is 1,609.344 metres. A nautical mile is 1,852 metres, based on one minute of latitude, and is used in aviation and maritime navigation. This tool converts statute miles; for nautical miles, multiply statute miles by 0.869.