Running Pace Calculator
Find my
Units
e.g. 50:00 or 1:45:30
Pace
5:00 /km
- Per km
- 5:00
- Per mile
- 8:03
- Speed
- 12.00 km/h · 7.46 mph
- Time · distance
- 50:00 · 10.00 km
Race predictions at the same effort
| 5K | 23:59 | 4:48 /km |
|---|---|---|
| 10K | 50:00 | 5:00 /km |
| Half marathon | 1:50:19 | 5:14 /km |
| Marathon | 3:50:01 | 5:27 /km |
Riegel's formula, T₂ = T₁ × (D₂ ÷ D₁)^1.06. It assumes training for the distance; predictions from a short race to the marathon are usually optimistic.
Even splits per km
- 1 km: 5:00
- 2 km: 10:00
- 3 km: 15:00
- 4 km: 20:00
- 5 km: 25:00
- 6 km: 30:00
- 7 km: 35:00
- 8 km: 40:00
- 9 km: 45:00
- 10 km: 50:00
Work out your running pace, finish time or distance from the other two, in kilometers or miles. The calculator converts between pace per kilometer and per mile, gives your speed and even splits, and predicts race times from 5K to the marathon with Riegel's formula.
Formula
Worked Example
50 minutes over 10 km is 5 minutes per kilometer, and since a mile is 1.609 km that is 8:03 per mile. Riegel's formula scales the time by the distance ratio raised to 1.06: 50 × (21.0975 ÷ 10)^1.06 ≈ 110.3 minutes for the half marathon.
Frequently Asked Questions
How do I convert pace per kilometer to pace per mile?
Multiply by 1.609. A pace of 5:00 per km is 8:03 per mile, and 10:00 per mile is 6:13 per km.
How accurate are marathon predictions from a 10K time?
Riegel's formula assumes you have trained for the longer distance. For the marathon it is often optimistic for runners without much long-run mileage, who tend to finish several percent slower than predicted; predictions between nearby distances, such as 10K to half marathon, are more reliable.
What pace do I need for a sub-2-hour half marathon or a 4-hour marathon?
The same pace for both: 5:41 per km, or 9:09 per mile, because the marathon is twice the distance and the target time is twice as long. Aim a few seconds faster to leave a margin.