Length Converter
Convert between metric and imperial lengths — millimetres to miles, feet to metres, inches to centimetres — using the exact international definitions of the inch (25.4 mm) and the mile (1,609.344 m). Results update as you type; exact factors shown.
One kilometre is 0.6214 miles — see the exact factor, not a rounded rule of thumb.
How the length converter works
Every length is converted through the metre, the SI base unit of length. The inch has been defined as exactly 25.4 mm since the 1959 international yard and pound agreement, so a foot is exactly 0.3048 m, a yard 0.9144 m and a statute mile 1,609.344 m. The nautical mile is 1,852 m by international definition.
Australia is fully metric under the National Measurement Act 1960; imperial units appear only in trade with the US and in older documents.
Common length conversions
| From | To | Units |
|---|---|---|
| 1 km | 0.6214 mi | kilometre to miles |
| 1 mi | 1.6093 km | mile to kilometres |
| 1 m | 3.2808 ft | metre to feet |
| 1 ft | 0.3048 m | foot to metres |
| 1 in | 2.54 cm | inch to centimetres |
| 1 cm | 0.3937 in | centimetre to inchs |
| 100 m | 109.3613 yd | metres to yards |
| 1 nmi | 1.852 km | nautical mile to kilometres |
| 5 km | 3.1069 mi | kilometres to miles |
| 10 mi | 16.0934 km | miles to kilometres |
Units in this converter and their exact factors
| Unit | Symbol | One unit in metres |
|---|---|---|
| millimetre | mm | 0.001 metre |
| centimetre | cm | 0.01 metre |
| metre | m | 1 metre |
| kilometre | km | 1,000 metre |
| inch | in | 0.0254 metre |
| foot | ft | 0.3048 metre |
| yard | yd | 0.9144 metre |
| mile | mi | 1,609.344 metre |
| nautical mile | nmi | 1,852 metre |
FAQFrequently asked questions about length conversion
How many centimetres are in an inch?
Exactly 2.54 cm. The inch was fixed at 25.4 mm by international agreement in 1959, so the conversion is exact, not approximate.
How many kilometres are in a mile?
One statute mile is exactly 1.609344 km. Five miles are a little over 8 km; ten kilometres are about 6.2 miles.
What is the difference between a mile and a nautical mile?
A statute mile is 1,609.344 m; a nautical mile is 1,852 m — about 15% longer. Nautical miles are used at sea and in aviation because one equals one minute of latitude.
How many feet are in a metre?
About 3.2808 feet. Exactly, 1 m = 1 / 0.3048 ft = 3.280839895… ft.
Are these conversions exact?
Yes for every imperial unit here: inch, foot, yard and mile are all defined as exact multiples of the metre. Only the displayed rounding is approximate.
Where these figures come from
- BIPM — The International System of Units (SI Brochure, 9th edition) — definitions of the base and derived units.
- NIST Special Publication 811 — Guide for the Use of the International System of Units — the exact conversion factors used here.
- National Measurement Institute (NMI) — Australia's national measurement authority.
Last checked: September 2026. Conversion factors are fixed by definition and do not change with tax years or regulations.