Length is measured in units such as mm, cm, m, km, in, ft, yd, mi. Pick a source and target unit above, enter a value, and the result appears instantly — free and entirely in your browser. Below you'll find the most common individual conversions as dedicated pages.
Which length units are there?
- Millimeter (mm) — The millimetre (mm) is one thousandth of a metre, the smallest common metric length unit. It is used for rainfall, screw sizes and material thickness.
- Centimeter (cm) — The centimetre (cm) is one hundredth of a metre. It is the everyday metric unit for body height, paper sizes and small objects in most of the world.
- Meter (m) — The metre (m) is the SI base unit of length. It is used for room sizes, sports distances and building dimensions, and anchors all other metric length units.
- Kilometer (km) — The kilometre (km) equals 1,000 metres and is the metric unit for road distances and travel in most countries.
- Inch (in) — The inch (in) is an imperial length unit defined as exactly 2.54 cm. It is used in the US and UK for screen sizes, body height and DIY measurements.
- Foot (ft) — The foot (ft) equals 12 inches or exactly 0.3048 m. It is the imperial unit for height and room dimensions in the US and UK.
- Yard (yd) — The yard (yd) equals 3 feet or exactly 0.9144 m. It is used for fabric, sports fields and short distances in the US and UK.
- Mile (mi) — The mile (mi) equals 1,609.344 m or 5,280 feet. It is the imperial unit for road distances in the US and UK.
Key facts about length
Most of the world measures length in metres and centimetres, while the US and UK also use inches, feet and miles. Converting between metric and imperial is a daily need for travel, DIY and online shopping.
By the 1959 international agreement, the inch is exactly 2.54 cm and the foot exactly 0.3048 m. So 1 metre = 3.2808 feet and 1 kilometre = 0.6214 miles.
How to use the length converter
- Pick the source unit and enter the length value.
- Pick the target unit — the result appears instantly.
- Use the swap button to reverse the direction.
Everything runs locally in your browser — no uploads, no waiting, no limits, and it even works offline.