Free Marathon Time Predictor
Predict your marathon finish time based on a shorter race result using the Riegel formula.
minutes
Predicted Marathon Time (min)
240.2 minutes
Marathon Time (hours)4.00 hours
Predicted Pace9.17 min/mile
Predicted Marathon Time (min) vs Recent Race Time
Riegel Formula
Predicted Time = Race Time x (Target Distance / Race Distance)^1.06
The Riegel formula, developed by Peter Riegel in 1977, accounts for the fact that pace slows as distance increases. The exponent 1.06 captures this endurance fatigue factor.
Example Calculation
A runner who completed a 5K (3.1 miles) in 25 minutes.
- 01Marathon distance = 26.2 miles
- 02Distance ratio = 26.2 / 3.1 = 8.452
- 03Predicted time = 25 x 8.452^1.06
- 04= 25 x 9.55 = 238.7 minutes
- 05= 3 hours 58.7 minutes
- 06Pace = 238.7 / 26.2 = 9.11 min/mile
Frequently Asked Questions
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