How to use the pace calculator
- Choose what to calculate: your pace, your finish time, or the distance you covered.
- Enter the other two values. Pick a race (5K, 10K, half marathon, marathon) to fill in the distance.
- Press Calculate for pace per kilometre and per mile, speed, split times and predicted race times.
Pace formulas
\text{pace} = \dfrac{\text{time}}{\text{distance}} \qquad \text{time} = \text{pace} \times \text{distance}Speed is the other way round – distance ÷ time. A pace of 6:00 per km is 10 km/h; 1 mile is 1.609344 km, so a pace per mile is 1.609 times the pace per km.
55 minutes ÷ 10 km = 5.5 minutes = 5:30 per km. Per mile: 5:30 × 1.609 = 8:51 per mile. Speed: 10 ÷ 55 × 60 = 10.9 km/h.
Race times at common paces
| Pace per km | Per mile | 5K | 10K | Half marathon | Marathon |
|---|---|---|---|---|---|
| 4:00 | 6:26 | 20:00 | 40:00 | 1:24:23 | 2:48:47 |
| 4:30 | 7:15 | 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 |
| 8:00 | 12:52 | 40:00 | 1:20:00 | 2:48:47 | 5:37:34 |
Predicting race times
The race predictions use Peter Riegel's formula (1981), which scales a known result to another distance:
T_2 = T_1 \times \left(\dfrac{D_2}{D_1}\right)^{1.06}The exponent 1.06 reflects slowing down over longer distances. It works best between about 1.5 km and the marathon, and only if you have trained for the longer race – most first-time marathoners run slower than the prediction.
55{:}00 \times (21.0975 / 10)^{1.06} = 2{:}01{:}21, about 5:45 per km.
Using pace in training
- Easy runs: most of your running, at a pace you could hold a conversation – often 60–90 seconds per km slower than 10K race pace.
- Tempo runs: comfortably hard, roughly the pace you could hold for an hour.
- Intervals: short repeats at around 5K pace or faster, with recovery jogs.
- Even splits: starting too fast is the most common racing mistake. The split table shows the time to aim for at each kilometre or mile.
Heart rate is another way to judge effort – see the target heart rate calculator. For the energy you use, try the calories burned calculator.
Frequently asked questions
How do I calculate my running pace?
Divide your time by the distance. 30 minutes for 5 km is 6 minutes per km; 30 minutes for 3 miles is 10 minutes per mile.
What is a good 5K time?
For recreational runners, around 25–35 minutes is common. Under 25 minutes (5:00 per km) is a strong time for most adults, but it depends on age and experience.
What pace do I need for a sub-4-hour marathon?
About 5:41 per km or 9:09 per mile, run evenly from start to finish.
How do I convert pace per km to pace per mile?
Multiply by 1.609. For example, 5:00 per km × 1.609 = 8:03 per mile.
How accurate are race time predictions?
Riegel's formula is a good guide from 5K to the half marathon. For the marathon it is often a few minutes optimistic unless your weekly mileage is high.