Race Time Predictor
Predict your time for another race distance from a recent result, using Riegel's endurance formula.
Predicted time
3:59:47
- Pace per km
- 5:41 /km
- Pace per mile
- 9:09 /mi
Assumes you train properly for the new distance; predictions from short races to the marathon are often optimistic.
Predictions for standard races
| Race | Predicted time | Pace /km | Pace /mi |
|---|---|---|---|
| Mile | 7:31 | 4:40 | 7:31 |
| 5K | 25:00 | 5:00 | 8:03 |
| 10K | 52:07 | 5:13 | 8:23 |
| Half marathon | 1:55:00 | 5:27 | 8:46 |
| Marathon | 3:59:47 | 5:41 | 9:09 |
Show the work
Time in seconds
t = h × 3,600 + min × 60 + s
0 × 3,600 + 25 × 60 + 0 = 1,500 s
Riegel's formula (seconds, shown as h:mm:ss)
T2 = T1 × (D2 ÷ D1) to the power of e
1,500 × (42.195 ÷ 5) to the power of 1.06 = 3:59:47
How it works
T₂ = T₁ × (D₂ ÷ D₁)^1.06 (Riegel, American Scientist 1981); the exponent can be changed
Questions
- How does the race time predictor work?
- T₂ = T₁ × (D₂ ÷ D₁)^1.06 (Riegel, American Scientist 1981); the exponent can be changed.
- What do I need to enter?
- Race you ran, Its distance, Unit, Your time — hours, Your time — minutes, Your time — seconds, Race to predict, Fatigue exponent. Optional fields can be left blank.
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