How does the race time predictor work?

It uses the Daniels-Gilbert formula to estimate your aerobic capacity from one recent race, then predicts equivalent finish times at every other standard distance.

How accurate are the race predictions?

Prediction ranges widen for longer events, where pacing strategy and fuelling introduce more variability, so treat longer-distance estimates as a window rather than a single guaranteed time.

Race Time Predictor

Predict finish times across all standard distances from a recent race result

Your recent race distance

Finish time

Predicted finish times

3:40 – 3:54

3:40–3:54 min/km

12:17 – 12:55

4:06–4:18 min/km

21:10 – 22:15

4:14–4:27 min/km

10K

43:53 – 46:08

4:23–4:37 min/km

15K

1:06:50 – 1:11:41

4:27–4:47 min/km

Half Marathon

1:35:45 – 1:43:43

4:32–4:55 min/km

Marathon

3:15:51 – 3:38:39

4:38–5:11 min/km

Ranges reflect research-backed confidence intervals (±2.5–5.5%) using the Daniels-Gilbert formula. Actual performance depends on race-specific conditions.

How predictions work

Uses the Daniels-Gilbert formula to estimate your aerobic capacity from one race, then predicts equivalent performances at other distances. Ranges widen for longer events where pacing strategy and fuelling introduce more variability.

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