Formula
value in target unit = value × (metres per source unit) ÷ (metres per target unit)
- 1 inch = 25.4 mm exactly
- 1 foot = 0.3048 m
- 1 mile = 1,609.344 m
- 1 nautical mile = 1,852 m
Convert to metres, then to the unit you want.
Worked example
1 mile in kilometres
- Value
- 1
- From
- Mile (mi)
- To
- Kilometre (km)
Mile to Kilometre
1.609344 km
In words: 1 mi = 1.609344 km
How it works
Since 1959 the inch has been defined as exactly 25.4 millimetres, and every other imperial length follows from it: a foot is 0.3048 m, a yard 0.9144 m and a mile 1,609.344 m. These definitions are exact, so conversions like miles to kilometres carry no hidden rounding.
The mile here is the international mile. The old US survey mile used for some land surveys differs by about two parts per million and is not included. A nautical mile (used at sea and in the air) is longer than a land mile at 1,852 m. For speeds in these units see the Speed Converter; for areas use the Area Converter, and for everything else the Unit Converter.
Assumptions and limits
- Metric prefixes and international imperial units only.
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