Running pace calculator
Enter any two of distance, time and pace to get the third — plus per-km and per-mile splits and predicted times for other race distances.
| Race | Same pace | Predicted (Riegel) |
|---|
| Split | Elapsed time |
|---|
On this page
How pace, time and distance fit together
Pace is just time divided by distance. Run 10 km in 55 minutes and your pace is 55 ÷ 10 = 5.5 minutes per km, which is 5:30 /km. Everything else follows from that one relationship:
- Pace = time ÷ distance
- Time = pace × distance
- Distance = time ÷ pace
To switch between units, one mile is 1.609344 km, so a 5:30 /km pace is 8:51 per mile. Speed is the same idea flipped around: 60 ÷ 5.5 = 10.9 km/h. There's a full walk-through in how to convert pace per mile to per km.
Pace chart for common race times
| Pace /km | Pace /mile | 5K | 10K | Half | Marathon |
|---|---|---|---|---|---|
| 4:00 | 6:26 | 20:00 | 40:00 | 1:24:23 | 2:48:47 |
| 4:30 | 7:14 | 22:30 | 45:00 | 1:34:56 | 3:09:53 |
| 5:00 | 8:03 | 25:00 | 50:00 | 1:45:29 | 3:30:59 |
| 5:30 | 8:51 | 27:30 | 55:00 | 1:56:02 | 3:52:04 |
| 6:00 | 9:39 | 30:00 | 1:00:00 | 2:06:35 | 4:13:10 |
| 6:30 | 10:28 | 32:30 | 1:05:00 | 2:17:08 | 4:34:16 |
| 7:00 | 11:16 | 35:00 | 1:10:00 | 2:27:41 | 4:55:22 |
Want the full version with more paces? See our running pace chart.
How the race predictions work
The "same pace" column simply assumes you could hold today's pace for any distance, which nobody can. The "predicted" column uses Riegel's formula, T₂ = T₁ × (D₂ ÷ D₁)1.06, which slows you down a little as the distance grows. It's a decent guide from 5K up to the half marathon. For the marathon it tends to be optimistic unless you've done the long runs, so treat it as a best case. More on setting a realistic target in how to pick a realistic marathon goal time.
Using pace in training
- Most runs should feel easy. Easy runs are usually 60–90 seconds per km slower than your 5K race pace. If you can't talk in full sentences, slow down.
- Race day: start controlled. Even or slightly faster second halves (negative splits) usually beat going out hard.
- Heat, hills and wind change everything. Pace targets are for flat, cool conditions. On a hot or hilly day, run by effort or heart rate instead.
- New to running? There's no "good" pace to aim for yet. Read what's a good running pace for beginners before you worry about the clock.
Frequently asked questions
How do I calculate my running pace?
Divide your total time by the distance. For example, 27 minutes 30 seconds for 5 km is 27.5 ÷ 5 = 5.5 minutes, or 5:30 per km (8:51 per mile).
What pace do I need for a sub-2-hour half marathon?
About 5:41 per km or 9:09 per mile, held for all 21.1 km. Most runners aim a few seconds faster to leave room for water stations and crowded starts.
What pace is a 4-hour marathon?
5:41 per km, or 9:09 per mile, across 42.2 km.
How do I convert pace per mile to pace per km?
Divide the pace per mile by 1.609. For example, a 9:00 per mile pace is 540 seconds ÷ 1.609 = 336 seconds, or 5:36 per km.
How accurate are race time predictions?
Riegel's formula is a reasonable estimate between similar distances when you've trained for the longer one. It's often optimistic for the marathon if your weekly mileage is low.
For general fitness information only. Check with a doctor before starting a new exercise programme, especially if you have a heart condition or haven't exercised in a while.