Running Pace Calculator
Pace per kilometre or mile and speed from a distance and a time, with predicted 5K to marathon times.
Pace
- Speed
- 12.00 km/h
- Distance
- 5 km
| Same effort over | Predicted time |
|---|---|
| 5K | 25:00 |
| 10K | 52:07 |
| Half marathon | 1:55:00 |
| Marathon | 3:59:47 |
- Predicted times use Riegel’s formula: a guide for a runner trained for the longer distance, usually optimistic at the marathon for anyone who is not.
Your run
How is this calculated?
Pace = time ÷ distance · Speed = distance ÷ time · Riegel: T₂ = T₁ × (D₂ ÷ D₁)^1.06Runs in your browser — nothing you enter leaves this device.
Predicted times are estimates for trained runners. Build up distance gradually, and check with a doctor before starting hard training if you have a medical condition.
About this tool
What it does
Give a distance and a time, and this calculator works out your pace per kilometre and per mile and your speed. It also predicts what the same effort would give over a 5K, 10K, half marathon and marathon, using Peter Riegel’s formula, which runners and coaches have used since 1977 to compare performances across distances.
How to use it
- Choose a race distance, or Other to enter your own in kilometres or miles.
- Type your time as hours:minutes:seconds (1:05:30), minutes:seconds (25:00) or words (1h 5m 30s).
- Choose whether to show pace per kilometre or per mile.
- Read your pace, speed and the predicted times for the other distances.
Limits and your data
- Riegel’s formula assumes you are trained for the longer distance. For a runner who has never run a marathon, the marathon prediction is usually too fast, often by 10 minutes or more.
- Predictions are most reliable between about 3 and 50 km, and from a recent, all-out effort rather than an easy run.
- Hills, heat, wind and course length change real race times; a GPS watch can also read a course a little long or short.
- Times are shown to the nearest second; the calculation keeps full precision until then.
- The calculation runs in your browser. Nothing is saved or sent anywhere.
Questions
What pace do I need for a sub-2-hour half marathon?
About 5:41 per kilometre, or 9:09 per mile. Choose Half, enter 1:59:59, and read the pace.
How do I convert pace per mile to pace per kilometre?
Divide by 1.609. An 8:00 mile is 4:58 per kilometre. Switch the “Show pace per” option and the calculator does it for you.
What is a good 5K time?
It depends on age, sex and training. Many recreational runners finish between 25 and 35 minutes; under 20 minutes is quick for most club runners. Compare yourself with your last race rather than anyone else.
Why does the prediction slow down more than the distance?
Because the exponent in Riegel’s formula is 1.06, not 1. Doubling the distance a little more than doubles the time: you cannot hold your 5K pace for a 10K.