Race Time Predictor (Riegel Formula)
Predict your race time based on a previous performance using the Riegel formula. Estimate your marathon time from a 10km or half-marathon result.
Calculator
Enter your reference performance and target distance
Estimated Time
3h 50min 2s
Target Pace
5:27 min/km
Important Note
This calculation assumes you have followed specific training for the target distance. The prediction is an estimate and may vary based on training, conditions, and individual factors.
Get a specific training planWhat is the Riegel Formula?
The Riegel formula is a mathematical model used to predict race times at different distances based on a known performance. It uses an exponential factor (1.06) that accounts for fatigue accumulation over longer distances. This formula is widely used by runners and coaches to estimate race times and set training goals.
How to use this predictor?
Enter your best recent performance (distance and time) as a reference. Then enter the distance you want to predict. The calculator will estimate your time and target pace. Remember that this is an estimate - actual performance depends on training, race conditions, and individual factors.