Km to Miles Converter
Convert kilometers to miles, or miles back to kilometers, using the exact international factor 1 mile = 1.609344 km. Enter a distance in km or mi and pick a direction.
Example: with Distance 10 · Direction Kilometers → Miles → Result: 6.214 mi.
- Written out10 km = 6.214 mi
- Conversion factor1 km = 0.621371 mi
Computed by the calculator below using its default values. Change any input to see your own numbers.
1 mile = 1.609344 km is the internationally agreed exact value from the 1959 yard and pound agreement. Divide km by 1.609344 to get miles; multiply miles by 1.609344 to get km.
Kilometers and miles, exactly
A mile and a kilometer both measure distance, but they come from different systems. The kilometer is metric — a thousand meters. The mile is defined against the meter through the international foot, which fixes one mile at exactly 1,609.344 meters, or 1.609344 km. That makes every conversion a single multiply or divide with no rounding built into the factor itself.
To go from kilometers to miles, divide by 1.609344. To go the other way, multiply. The rough shortcut of multiplying km by 0.62 is close, but the exact factor 0.621371 matters once distances get long: a road trip of a few hundred kilometers can drift a mile or two off if you round the factor too early.
How it’s calculated
Miles = kilometers ÷ 1.609344; kilometers = miles × 1.609344. One mile is exactly 1,609.344 m by the 1959 international agreement that defined the yard as 0.9144 m. Results are rounded to 4 decimal places for display.
Applies to the statute (land) mile. Nautical miles differ (1 nmi = 1.852 km) and are not used here.
Kilometers to miles reference
| Kilometers | Miles |
|---|---|
| 1 km | 0.6214 mi |
| 5 km (parkrun) | 3.1069 mi |
| 10 km | 6.2137 mi |
| 21.0975 km (half) | 13.1094 mi |
| 42.195 km (marathon) | 26.2188 mi |
| 100 km | 62.1371 mi |
Computed as km ÷ 1.609344, the exact number of kilometers in one statute mile.
Common mistakes
- Using 1.6 as the factor — fine for mental math but off by about 0.6%, roughly a quarter mile over a marathon.
- Confusing statute miles with nautical miles (1.852 km) used in aviation and at sea.
- Multiplying instead of dividing when converting km to miles, which overstates the distance by more than 2.5 times.
Frequently asked questions
What is the formula for km to miles?
Miles = kilometers ÷ 1.609344. To reverse it, multiply miles by 1.609344 to get kilometers.
How many miles is 10 km?
10 km ÷ 1.609344 = 6.2137 miles, a bit over six and a quarter miles. A 5 km run is about 3.11 miles.
Is multiplying by 0.62 accurate enough?
For a quick estimate, yes. But the exact factor is 0.621371, so 0.62 undercounts long distances by a few tenths of a mile per hundred km.
Does this work for nautical miles?
No. A nautical mile is 1.852 km, used for sea and air navigation. This tool uses the statute land mile of 1.609344 km.