Marathon Pace & Race-Time Predictor
Work out your pace, speed and per-kilometer splits — or take one recent result and predict your 5K, 10K, half and full marathon times.
| Split | Cumulative |
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Enter one recent race result. We project your equivalent times at every other distance with Riegel's formula.
| Race | Predicted | Pace/km |
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Estimates assume comparable training and conditions — real results vary with course, weather and distance-specific preparation.
How is pace calculated?
Pace is simply time divided by distance. This tool also converts it to min/mile and km/h, then breaks your race into per-kilometer splits so you can plan an even effort from the gun.
How does the predictor work?
It uses Riegel's formula: T2 = T1 × (D2 / D1)^1.06. It's a well-known endurance model — accurate for similar effort levels, less so when jumping from very short to very long distances without specific training.