T₂ = T₁ × (D₂ ÷ D₁)1.06
T₁ is your time, D₁ is the distance you raced and D₂ is the distance you want to predict. The exponent of 1.06 reflects how pace slows as distance increases. Double the distance and your time grows by about 4% more than double.
Common 10K times from 40 to 70 minutes, converted to other distances with the Riegel formula.
| 10K time | 5K | Half | Marathon |
|---|---|---|---|
| 40:00 | 19:11 | 1:28:15 | 3:04:00 |
| 45:00 | 21:35 | 1:39:17 | 3:27:01 |
| 50:00 | 23:59 | 1:50:19 | 3:50:01* |
| 55:00 | 26:23 | 2:01:21 | 4:13:01* |
| 1:00:00 | 28:47 | 2:12:23 | 4:36:01* |
| 1:05:00 | 31:11 | 2:23:25 | 4:59:01* |
| 1:10:00 | 33:34 | 2:34:27 | 5:22:01* |
It is an estimate based on Peter Riegel's formula, T₂ = T₁ × (D₂ ÷ D₁)^1.06. It is most reliable when the two distances are close and you have trained for the distance you want to predict. Course, weather and how you feel on race day are not included, so use it as a starting point when you set a goal.
Yes, but the prediction assumes you have done the endurance training for a marathon. The bigger the gap between the two distances, the further the prediction may be from your actual time.
This tool provides general calculations and scheduling suggestions. It does not provide a medical diagnosis, treatment or personalized medical advice.