Sports & Games
Race Time Predictor
Lets users plan and decide race time predictor instantly with formula, steps and examples — no manual math.
Enter your details
km
km
Your result
Predicted time
1h 55m
Riegel prediction for 21.1 km ≈ 1h 55m (5:27/km).
Required pace
5:27/km
About this calculator
Riegel's formula predicts race times: T₂ = T₁ × (D₂/D₁)^1.06. The 1.06 fatigue exponent accounts for slowing over longer distances. Accurate for well-trained runners at similar effort.
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