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Marathon Race Predictor
Predict your Marathon, Half Marathon, or 10K finish time using Riegel's Formula based on your best recent race result.
::
| Distance | Predicted Time | Avg Pace /km |
|---|---|---|
| 5K | 25m 0s | 5:00 |
| 10K | 52m 7s | 5:13 |
| Half Marathon | 1h 55m 0s | 5:27 |
| Marathon | 3h 59m 47s | 5:41 |
| 50K Ultra | 4h 47m 2s | 5:44 |
*Based on Riegel's Formula (Exponent 1.06). Accuracy decreases as distance increases significantly beyond your input.
How Accurate are Race Predictors?
This calculator uses Pete Riegel's formula (T2 = T1 * (D2 / D1)^1.06), which was widely popularized by Runner's World. It assumes you have done the appropriate training for the longer distance.Limitations
- Endurance Base: A fast 5K time does not guarantee a fast marathon if you haven't put in the long runs. The formula predicts potential, not magic.
- Course Conditions: A flat 10K cannot accurately predict a hilly marathon time.
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