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. Don't forget that temperature and your choice of shoes can also impact your race time.
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.