Race Time Predictor
Predict your race times for 5k, 10k, Half, and Marathon
Ran a fast 5K and wondering what your Marathon potential is? This calculator uses the Riegel formula to project your performance across different distances.
Calculator Inputs
Results
Enter values above to see your results
How It Works
Formula: T2 = T1 × (D2 / D1)^1.06. This assumes proper training for the target distance.
Tips & Best Practices
- •Predictions get less accurate the further the target distance is from your input run.
- •Endurance training is required to hit the predicted Marathon time.
Frequently Asked Questions
Is this accurate?
It's widely used but can be optimistic for new runners moving up to the Marathon distance.
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