Running pace & race predictor
Enter a recent run and get your pace plus predicted times at other distances, using the Riegel formula with exponent 1.06.
km
How it works
Pace = time ÷ distance. Predictions use Riegel's formula T2 = T1 × (D2 ÷ D1)^1.06, which models the gradual slowdown over longer distances.
Predicting a marathon from a 5K tends to be optimistic; a half-marathon time is the most reliable basis for a full.
Assumptions
- Riegel exponent 1.06 (typical trained runner)
- Terrain, temperature and elevation ignored
FAQ
What marathon time does a 55-minute 10K predict?
About 4:14 by Riegel. Runners with limited long-run mileage often come in slower.