Running Pace & Race Predictor
Pace, splits, and predicted race times across distances.
Pace per mi
9:01
About
Three modes. Calculate pace from distance and time. Calculate finish time from pace and distance. Or predict your time at a different distance using a recent race result. Predictions use Riegel's formula, the standard model for endurance race time scaling.
How to use
- Pick a mode: pace, time, or predict.
- Enter the inputs (distance, time, pace).
- In Predict mode, enter a recent race time and see equivalents at common distances.
FAQ
What's Riegel's formula?+
T2 = T1 × (D2/D1)^1.06. The exponent 1.06 captures that longer races are slightly slower per mile due to fatigue. Works well within about 3× the original distance. Less accurate for huge extrapolations.