About Race Time Predictor
Predict marathon, half marathon, and 10k finish times using Pete Riegel’s endurance formula.. Designed for accurate, instantaneous calculations with zero wait time.
Formula
T2 = T1 × (D2 / D1)^1.06
Example Calculation
A 22-minute 5K predicts a 45:45 10K and a 3:33:00 Marathon.
How to Use
- Enter your values into the form fields above.
- The calculation updates immediately in real time.
- Inspect the main summary and secondary breakdowns below.