Calculate pace, time or distance, see km/mile splits, and equivalent race times across distances with the Riegel formula.
Pace is the time it takes to cover one unit of distance, usually expressed in minutes per kilometer or per mile. The three variables (total time, distance and pace) follow a direct relationship: time = pace x distance. Given any two, the third is derived mathematically. The Riegel formula, published by Peter Riegel in 1977 and still used today by race prediction calculators, estimates the expected time at a different distance from a known result: T2 = T1 x (D2/D1)^1.06. The 1.06 exponent (instead of 1.0) reflects that performance drops non-linearly as distance increases, doubling the distance costs about 6% more time per unit than a simple linear extrapolation would predict, reflecting the effect of accumulated fatigue.
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It is the time needed to cover one unit of distance, usually expressed in minutes and seconds per kilometer (e.g. 5:30/km) or per mile. It is the inverse of speed: the lower the pace, the faster the runner is moving.
| Split | Cumulative time |
|---|---|
| 1 | 5:00 |
| 2 | 10:00 |
| 3 | 15:00 |
| 4 | 20:00 |
| 5 | 25:00 |
Estimate from the Riegel formula (T2 = T1 x (D2/D1)^1.06), which models the performance drop-off at longer distances. It is a statistical prediction, not a guarantee, factors like specific training, weather and course profile change the real result.
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