Ultra time predictor
A marathon or half in. Your ultra out.
Type a recent marathon or half time. We project your 50K finish using the Riegel formula. Caveat: ultra terrain and elevation can add 5-15% to predictions.
What did you run?
Units
1
Distance
Pick a preset or type any distance.
km
Quick distances:
2
Finish time
Hours, minutes, seconds.
Hours
Minutes
Seconds
Examples
Marathon
3:50:01
Predicted finish at Marathon
From 10K in 50:00, here are your projected race times.
Find Marathon races →Predicted race times
Common ultra (50K) predictions
Reference table — popular race times and the Riegel-projected 50K. Real ultra finishes tend to be slower due to terrain, elevation, and fueling demands.
| Input race result | Predicted | Notes |
|---|---|---|
| Marathon 3:00:00 | 50K ~3:38 | Elite ultra territory. |
| Marathon 3:30:00 | 50K ~4:13 | Strong amateur ultra. |
| Marathon 4:00:00 | 50K ~4:48 | Solid first-50K target. |
| Marathon 4:30:00 | 50K ~5:23 | Comfortable 50K finish. |
| Half 1:45:00 | 50K ~4:23 | From half is risky — half is < ½ of 50K. |
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