Pace — the time it takes to cover one kilometer or mile — is the standard way runners track and compare performance. This calculator finds your pace from any distance and time, in both kilometers and miles.
The formula
For a 5 km run completed in 25 minutes: pace = 25 ÷ 5 = 5:00 per km. Converting to miles: 5:00 × 1.60934 ≈ 8:03 per mile.
Worked examples
| Distance | Time | Pace per km |
|---|---|---|
| 10 km | 50 min | 5:00 /km |
| 21.1 km (half marathon) | 1:45:00 | 4:58 /km |
| 42.2 km (marathon) | 4:00:00 | 5:41 /km |
Using pace to plan a race
Once you know your pace from a recent run or race, you can estimate finish times for other distances by multiplying pace by the new distance — though pace typically slows somewhat over longer distances due to fatigue, so this gives an optimistic estimate rather than a guaranteed prediction.
Common mistakes
- Mixing up pace and speed. Pace (time per distance) and speed (distance per time) are inverses of each other — a faster runner has a lower pace number but a higher speed number.
- Forgetting warm-up/cool-down time. If your total time includes walking or warm-up laps, your true running pace will be faster than the calculated average.
Frequently asked questions
How do I calculate my running pace?
Divide your total time by the distance covered. For example, 25 minutes over 5 km gives a pace of 5 minutes per kilometer.
How do I convert pace per km to pace per mile?
Multiply your per-kilometer pace by 1.60934, since one mile equals approximately 1.60934 kilometers.
Does pace stay the same over longer distances?
Not usually — most runners slow down somewhat over longer distances due to fatigue, so a pace from a shorter run tends to be optimistic when applied to a longer race.