Race Predictor

Predict your finish time at any distance based on a recent race, using the Riegel formula (T₂ = T₁ × (D₂/D₁)^1.06).

KNOWN RACE DISTANCE

YOUR FINISH TIME

hours

minutes

seconds

Distance	Predicted Time	Avg Pace
1 Mile	4:32	4:32/mi
5K	15:06	4:52/mi
8K ✓	25:00	5:00/mi
10K	31:29	5:04/mi
15K	48:23	5:11/mi
Half Marathon	1:09:27	5:18/mi
25K	1:23:08	5:21/mi
30K	1:40:52	5:25/mi
Marathon	2:24:48	5:31/mi

The Riegel formula (1977) models the relationship between distance and performance. It assumes consistent fitness and race conditions, results may vary with pacing strategy, terrain, and temperature.