Race Time Predictor Between Distances
Enter a reference time and a distance, and discover your theoretical times on other distances (5k, 10k, half-marathon, marathon...). This calculation is based on Riegel's formula, widely used in performance calculators.
The calculator takes into account the runner's profile (beginner, regular, well-trained) to adjust predictions.
Use your last time to predict your times
Estimated equivalent times
| Distance | Predicted time | Average pace |
|---|---|---|
| Enter your time and click "Calculate equivalences" to see predictions. | ||
About Riegel's formula
Estimates are based on Riegel's formula, used by many performance
calculators (race predictors). It links a reference time T1 on a distance D1
to a predicted time T2 on a distance D2:
- Valid mainly for efforts between 3.5 minutes and 4 hours.
- Assumes you are trained for the target distance (a 10k doesn't predict a 100k!).
- The further the target distance from your reference distance, the more approximate the result.
To further refine your forecasts, you can also check your VO₂ max, calculate your specific training paces and adjust your plan according to your heart rate.
Who was Peter "Pete" Riegel?
- American mechanical engineer (1935–2018) passionate about distance running.
- Specialist in official road course measurement and active volunteer in the running community.
- Author in 1977, in Runner's World, of the simple formula that predicts time on another distance: the famous Riegel curve.