Race Predictor: Running Time Calculator

Your details

Select the race you already ran and have a finish time for.
Hours part of your finish time (0 for races under an hour).
h
Minutes part of your finish time.
min
Seconds part of your finish time.
sec
The upcoming race you want to predict a time for.
Predicted finish timeRecreational runner
3:43:07

Estimated finish time for your target race using the Riegel formula

Pace per kilometre5:17
Pace per mile8:31
Known race pace (per km)4:51
5K predicted23:16
10K predicted48:30
Half Marathon predicted1:47:01
Marathon predicted3:43:07
5K seconds1,396
10K seconds2,910
Half Marathon seconds6,421
Marathon seconds13,387
5K1,396
10K2,910
Half Marathon6,421
Marathon13,387

Predicted Marathon finish: 3:43:07

  • Your predicted finish time for the Marathon is 3:43:07.
  • You would need to run at 5:17 per kilometre (8:31 per mile) on average.
  • This is extrapolated from your 10K time of 48:30 using the Riegel formula.
  • The Riegel formula becomes less accurate when the target distance is much longer than your known race. Consider training specifically for the longer event before relying on this estimate.

Next stepThis prediction assumes you are equally trained for both distances. For the most accurate marathon estimate, use a race within 6 weeks and no longer than a half marathon as your input.

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