Race Time Predictor
Enter a known race time and we will predict your finish times for other distances using the Riegel formula.
The Riegel Formula
T2 = T1 x (D2 / D1)^1.06 Where T1 is your known time, D1 is the known distance, D2 is the target distance, and T2 is the predicted time. The exponent 1.06 accounts for the fatigue factor over longer distances.
Accuracy
The Riegel formula works best for well-trained runners predicting within a reasonable range (e.g., 5K to marathon). Predictions are less accurate for untrained runners or extreme distances.