Length
Metric and imperial lengths
The Length Converter handles the everyday units of distance and dimension: millimetres, centimetres, metres, kilometres, inches, feet, yards, and miles. Type a value in any unit and the others update instantly.
Length conversions trip people up because the relationships between imperial units (inches → feet → yards → miles) are not powers of ten, while metric units are. Mixing them — like asking "how many feet in 1.5 km?" — is exactly the case this converter is built for.
Supported units
- Metric: millimetre (mm), centimetre (cm), metre (m), kilometre (km)
- Imperial / US: inch (in), foot (ft), yard (yd), mile (mi)
Key conversion factors
- 1 inch = exactly 25.4 millimetres
- 1 foot = 12 inches = 0.3048 metres
- 1 yard = 3 feet = 0.9144 metres
- 1 mile = 5,280 feet = 1.609344 kilometres
- 1 metre = 100 cm = 1000 mm
- 1 kilometre = 1000 metres
The inch-to-millimetre relationship is defined to be exact, which makes all other conversions derived rather than approximate.
Worked example
Convert 6 feet 2 inches to centimetres:
- Convert everything to inches:
6 × 12 + 2 = 74 inches - Convert inches to cm:
74 × 2.54 = 187.96 cm
Or convert 5 km to miles: 5 / 1.609344 ≈ 3.107 miles.
Common use cases
Travel (estimating distances on foreign maps), DIY projects (converting between an imperial tape measure and metric instructions), shipping (parcel dimensions), sports (race distances), and homework. Particularly useful for anyone working across the US and the rest of the world.
Precision note
This converter rounds display to a sensible number of decimal places. For technical work where exact precision matters (machining, scientific instruments), use the conversion factors directly rather than the rounded display value.
Frequently asked questions
How many feet in a metre?
Approximately 3.28084 feet, or 1 metre = 39.37 inches.
How many kilometres in a mile?
Exactly 1.609344 kilometres. A useful mental approximation: 5 miles ≈ 8 km.
Is 1 cm exactly equal to anything in inches?
1 cm = 0.393700787... inches — not a round number, because the metric and imperial systems were defined independently. The inch was redefined in 1959 to be exactly 25.4 mm to nail this relationship down.