Most of the world times runners in minutes per kilometer. The United States and the United Kingdom mostly use minutes per mile. Both conventions describe the same effort, and switching between them is a pure unit conversion — no fitness math involved.
The exact conversion
One international mile is exactly 1609.344 meters. Therefore a per-mile pace is always 1.609344 times the corresponding per-km pace: it takes longer to cover a mile than a kilometer at the same speed. To convert per-km pace to per-mile pace, multiply the seconds by 1.609344. To go back, divide by 1.609344.
Comparison table
| Pace per km | Pace per mile | Speed |
|---|---|---|
| 4:00 /km | 6:26 /mi | 15.00 km/h |
| 4:30 /km | 7:15 /mi | 13.33 km/h |
| 5:00 /km | 8:03 /mi | 12.00 km/h |
| 5:30 /km | 8:51 /mi | 10.91 km/h |
| 6:00 /km | 9:39 /mi | 10.00 km/h |
| 6:30 /km | 10:28 /mi | 9.23 km/h |
The pace calculator shows both pace units plus both speed units for any distance and time, so you can sanity-check any conversion in one step.
Mental math that holds up
Multiplying by 1.6 is close enough for conversation: 5:00 per km becomes 8:00 per mile, and the exact figure is 8:03. If you need more precision without a calculator, multiply by 1.6 and then add about 1.5 percent more. Watch displays that toggle units do the exact math for you mid-run.
Distances convert too, and it pays to memorize the common ones: 5K is 3.107 miles, 10K is 6.214 miles, a half marathon is 13.109 miles, and a marathon is 26.219 miles. Race results boards, GPS watches and entry forms mix these freely.
Practical pitfalls
Three mix-ups account for most conversion mistakes. First, confusing the direction: per-mile pace numbers are always larger than the matching per-km pace. Second, converting pace with a speed factor or vice versa — pace uses multiplication by 1.609344, speed uses division. Third, re-deriving one unit from a rounded display of the other, which compounds rounding errors. Keep one canonical value in exact units and convert from it, which is exactly how RunPaceKit stores numbers internally.