Running Pace Calculator
Pace is how long it takes you to cover one mile or one kilometer — the number runners use to hold a steady effort. Enter a distance and a finish time to see your pace both ways, your speed, and predicted times for the classic race distances.
Your numbers
Result
- Speedmph
- 7.46
- Speedkm/h
- 12
| Distance | Predicted time |
|---|---|
| 5K | 25:00 |
| 10K | 52:07 |
| Half marathon | 1:55:00 |
| Marathon | 3:59:47 |
How pace is calculated
Pace is simply time ÷ distance. Run 5 km in 25:00 and your pace is 5:00 per km — and because a mile is longer than a kilometer, the same run is about 8:03 per mile. A lower pace number means you are running faster. Speed is the same information turned inside out: 5:00/km is 12 km/h.
Pace per mile vs per km
A mile is 1.609 km, so your per-mile pace is always the bigger number — you spend more time covering the longer unit. US races and treadmills usually speak in miles; most of the world and every standard road race (5K, 10K, marathon) is metric. This calculator shows both so you never have to convert in your head mid-run.
Predicting other race distances
From one result, the Riegel formula estimates your time at another distance: T2 = T1 × (D2 ÷ D1)^1.06. The 1.06 exponent captures that pace fades slightly as races get longer. The table projects the 5K, 10K, half and full marathon — but it assumes you have actually trained for that distance. Without the endurance base, a real marathon will be slower than the prediction, and heat, hills and wind all move the number too.
Informational and educational result. Not a substitute for professional advice.
Frequently asked questions
Sources
- Peter Riegel — race time prediction model (1981)
- USA Track & Field — standard road race distances
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