About the mi to km calculation
One mile is exactly 1.6093 kilometers, so converting between them is a single multiplication. Enter any value above and the result updates as you type. Road distances in the US and UK. Defined as exactly 1,609.344 metres since 1959. The standard road-distance unit in most of the world.
Formula
km = mi × 1.6093
1 mi = 1.6093 km
1 km = 0.621371 miWorked example
To convert 5 mi, multiply by 1.6093: 5 × 1.6093 = 8.0467 km.
Frequently asked questions
How many kilometers are in a mile?
There are 1.6093 kilometers in one mile. To convert any amount, multiply the number of miles by 1.6093.
How do I convert kilometers back to miles?
Divide instead of multiplying, or equivalently multiply by 0.621371. One kilometer is 0.621371 miles.
Is this conversion exact?
Yes. Since the international agreement of 1959, the relationship between miles and kilometers is defined exactly rather than measured, so the only rounding here is in how many decimal places we show.
Where is each of these units used?
Miles: road distances in the US and UK. Defined as exactly 1,609.344 metres since 1959. Kilometers: the standard road-distance unit in most of the world.
Sources
- NIST Special Publication 811 — Guide for the Use of the International System of Units