Race Time Predictor

Predict times across distances using Riegel's formula.

DistancePredicted timePace / km
5 km 00:25:00 05:00
10 km 00:52:07 05:12
Half marathon 01:55:00 05:27
Marathon 03:59:46 05:40

About this tool

Enter a known race time at a base distance — get predicted times at 5 km, 10 km, half marathon and marathon distances using the Riegel exponent.

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