KM to Miles Converter
Exact both ways — with the race distances runners actually look up.
Type in either field — the other updates instantly.
KM to Miles chart
| Kilometers | Miles |
|---|---|
| 1 km | 0.62 mi |
| 5 km | 3.11 mi |
| 10 km | 6.21 mi |
| 15 km | 9.32 mi |
| 20 km | 12.43 mi |
| 21.0975 km | 13.11 mi |
| 25 km | 15.53 mi |
| 30 km | 18.64 mi |
| 42.195 km | 26.22 mi |
| 50 km | 31.07 mi |
| 100 km | 62.14 mi |
| 160 km | 99.42 mi |
| 200 km | 124.27 mi |
| 300 km | 186.41 mi |
| 500 km | 310.69 mi |
| 1,000 km | 621.37 mi |
21.0975 km = half marathon · 42.195 km = marathon
How this is calculated
miles = km ÷ 1.609344 (exact — the mile is defined as 1,609.344 m)
A 5K is 3.11 miles, a 10K is 6.21, a half marathon (21.0975 km) is 13.11, and the marathon (42.195 km) is 26.22 — the chart carries all four because race distances are what this conversion gets asked for most.
The statute mile is defined as exactly 1,609.344 meters, so the conversion is exact; the ×0.62 shortcut is a rounding of the true 0.621371.
Kilometres to miles is the direction of a metric driver reading British or American signage, and of runners comparing race distances across conventions. A 10 km is 6.21 miles; a marathon is 42.195 km or 26.219 miles, a distance fixed at the 1908 London Olympics to place the finish in front of the royal box and standardised permanently in 1921.
The Fibonacci trick is worth knowing because it needs no arithmetic: consecutive Fibonacci numbers approximate the ratio, so 5 km is about 3 miles, 8 km about 5, 13 km about 8, 21 km about 13. That last one is a half marathon, and 13.1 miles is the correct answer — the approximation is good to within a percent across the useful range.
Frequently asked questions
How many miles is 1 km?
0.621371 miles. The mile is defined as exactly 1.609344 km, so km → miles is a division by that constant.
How many miles is a 5K and a 10K?
A 5K is 3.11 miles and a 10K is 6.21 miles. The half marathon (21.0975 km) is 13.11 miles and the full marathon (42.195 km) is 26.22 miles — all four are in the chart.
How do I convert km/h to mph?
Same factor — divide by 1.609344. 100 km/h is 62.14 mph. For speeds specifically, use the km/h to mph converter, which includes a speed-limit chart.
Why 1.609344 exactly?
The international mile is defined as 5,280 feet with the foot at exactly 0.3048 m: 5,280 × 0.3048 = 1,609.344 m. Definition, not measurement — so the conversion is exact.