How to convert miles to km?
Type a value in either box, and the answer shows it in the other unit as you type.
- Kilometers (km)
- 1.609344
1 mi = 1.609344 km.
Kilometers (km): 1.609344. 1 mi = 1.609344 km.
Kilometers (km) by miles (mi)
How to calculate
Converts miles (mi) to kilometers (km) and back, with the exact unit definitions.
Example with the default inputs (Miles (mi) 1): 1 mi = 1.609344 km.
Formula: km = mi × 1.609344
- 1 mile = 1.609344 kilometers, from the exact definitions in NIST SP 811.
- Exact on the typed decimals: at most 6 decimal places (6 significant digits below 0.0001), rounded half up; an answer of 1 billion or more shows at most 15 significant digits.
Worked examples
Each example is checked against the calculator on every build.
- Miles (mi) 1 gives Kilometers (km) 1.609344.Source: Exact unit definitions in NIST SP 811 (2008), Appendix B.8
- Miles (mi) 26.2 gives Kilometers (km) 42.164813.Source: Exact unit definitions in NIST SP 811 (2008), Appendix B.8
- Kilometers (km) 42.164813 gives Miles (mi) 26.2.Source: Exact unit definitions in NIST SP 811 (2008), Appendix B.8
Other questions people ask
How many kilometers are in a mile?
1 mile is 1.609344 kilometers, from the exact unit definitions (NIST SP 811).
How do I convert miles to km?
Multiply by 1.609344: km = mi × 1.609344. For example, 1 mi × 1.609344 = 1.609344 km.
How do I convert km back to miles?
Multiply by 0.621371, or type the kilometers into the second box and the converter works it out. 1 kilometer is 0.621371 miles.
What is 26.2 miles in km?
42.164813 km: 26.2 × 1.609344.
Why multiply by 1.609344?
A mile is exactly 1.609344 km: 5,280 feet of 0.3048 m (NIST).