Your Recent Race
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H : M : S
Enter your official chip time. For best results use a race from the last 8 weeks.
The Riegel formula uses an exponent to model how pace slows with distance. 1.06 works for most trained runners. Adjust if you consistently over or underperform at longer distances.
Enter a race result
to see your predictions
Predicted Finish Times
About the Riegel Formula —
T2 = T1 × (D2 ÷ D1)^1.06. Developed by Peter Riegel in 1977, it remains the most widely used model for predicting race times across distances. It assumes consistent training and race conditions — it tends to be optimistic for runners undertrained at longer distances and conservative for those with a strong endurance base.