How to convert kilometers to miles
- Type a distance in the Kilometers (km) box. The page opens with 5.
- Read the answer in the Miles (mi) box and in the result line under it. To go the other way, type in the Miles box and the Kilometers box updates.
- Choose Decimal places from 2 to 6. The default is 4.
- Tap a button under Common distances, such as Half marathon, to load a race distance.
The formula
One international mile is exactly 1.609344 kilometers, a value fixed by the 1959 international yard and pound agreement. NIST lists the mile as 1,609.344 meters. So miles = kilometers ÷ 1.609344 and kilometers = miles × 1.609344. Dividing by 1.609344 is the same as multiplying by 0.621371192. For a quick estimate in your head, divide kilometers by 1.6 (within 1 percent) or multiply by 0.6 (about 3 percent low).
Worked example: 5 km in miles
With the default input the tool works out 5 ÷ 1.609344 = 3.10685596... and shows 5 km = 3.1069 miles, rounded to 4 decimal places. The Miles box shows 3.1069. Typing 5 in the Miles box instead gives 8.0467 km, because 5 × 1.609344 = 8.04672.
Race distances in kilometers and miles
| Race | Kilometers | Miles |
|---|---|---|
| 5K | 5 km | 3.1069 mi |
| 10K | 10 km | 6.2137 mi |
| Half marathon | 21.0975 km | 13.1094 mi |
| Marathon | 42.195 km | 26.2188 mi (26 miles 385 yards) |
| 50K ultra | 50 km | 31.0686 mi |
| 100 km | 100 km | 62.1371 mi |
| 100 miles | 160.9344 km | 100 mi |
Kilometers to miles chart
| Kilometers | Miles | Kilometers | Miles |
|---|---|---|---|
| 1 km | 0.62 mi | 20 km | 12.43 mi |
| 2 km | 1.24 mi | 25 km | 15.53 mi |
| 3 km | 1.86 mi | 30 km | 18.64 mi |
| 4 km | 2.49 mi | 40 km | 24.85 mi |
| 5 km | 3.11 mi | 50 km | 31.07 mi |
| 6 km | 3.73 mi | 60 km | 37.28 mi |
| 7 km | 4.35 mi | 70 km | 43.5 mi |
| 8 km | 4.97 mi | 80 km | 49.71 mi |
| 9 km | 5.59 mi | 90 km | 55.92 mi |
| 10 km | 6.21 mi | 100 km | 62.14 mi |
| 15 km | 9.32 mi | 200 km | 124.27 mi |
Limits and edge cases
The tool uses the international mile. Old US survey maps use the survey mile, about 3 millimeters longer, and NIST has told users to avoid the survey foot since January 1, 2023, so the difference only matters for legacy land records. A nautical mile is a different unit (1.852 km), so use the length converter for that. Negative distances are rejected, commas work as thousands separators (1,000), and a tiny distance never shows as 0. Rounding affects only the display, never the math.
The same factor converts speed, so 100 km/h is 62.1371 mph. For many units at once use the unit converter or the speed converter, and to turn a finish time into splits try the marathon pace calculator.
Frequently asked questions
How many miles is a 5K?
A 5K is 5 kilometers, which is 3.1069 miles, or about 3.1. A 10K is 6.2137 miles.
How many miles is 100 km?
100 km is 62.1371 miles. The same factor applies to speed, so 100 km/h is about 62 mph.
Is a mile longer than a kilometer?
Yes. A mile is 1.609344 km, about 60 percent longer. A kilometer is about 0.62 of a mile.
How many miles is a marathon in kilometers?
A marathon is 42.195 km, which is 26.2188 miles (26 miles 385 yards). A half marathon is 21.0975 km, or 13.1094 miles.
How do I convert km to miles in my head?
Divide by 1.6 or multiply by 0.6. For 80 km, 80 ÷ 1.6 = 50 miles. The exact answer is 49.7097 miles.
Sources: NIST SP 811, Appendix B.9 (mile = 1,609.344 m), NIST on the US survey foot, and World Athletics for the marathon distance.