Sports & Fitness calculator
Race Time Predictor
Predict race time for another distance from a recent race result using the Riegel formula.
Formula
Riegel race prediction
Race predictions assume similar training, terrain, weather, and effort.
Predicted time = current time x (target distance / current distance)^1.06
A 25 minute 5K predicts roughly 52 minutes for 10K.
FAQs
Why is the exponent above 1?+
Longer races are usually run at a slightly slower pace than shorter races.
Does this work for all distances?+
It is a planning estimate and works best for reasonably related running distances.
How does the Race Time Predictor calculate the result?+
It uses the Riegel race prediction: Predicted time = current time x (target distance / current distance)^1.06. A 25 minute 5K predicts roughly 52 minutes for 10K.
What information do I need to use the Race Time Predictor?+
Predict race time for another distance from a recent race result using the Riegel formula.
How accurate is the Race Time Predictor?+
Race Time Predictor applies the formula and assumptions shown on this page. Results may be rounded for readability, so verify changing rates, thresholds, medical guidance, or legal rules with the cited source or a qualified professional.
What should I check before using the Race Time Predictor result?+
Check that the units, dates, rates, and assumptions match your situation. Change one input at a time to understand which values have the largest effect on the result.
Sports & Fitness guide
How to use the Race Time Predictor
Predict race time for another distance from a recent race result using the Riegel formula. The page also explains the riegel race prediction and shows a practical example: A 25 minute 5K predicts roughly 52 minutes for 10K.
- 1
Enter your details
Enter a recent race result using the Riegel formula, then complete any other fields shown in the calculator.
- 2
Check the calculation
Review the result alongside the riegel race prediction: Predicted time = current time x (target distance / current distance)^1.06.
- 3
Compare scenarios
Change one or more inputs to see how they affect the race Time Predictor result before you use the estimate.
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