Race Time Predictor
Predict a race time at a new distance from a known result (Riegel formula).
Result
Predicted time (min)
52.1
Target pace (min/km)
5.21
How it works
t₂ = t₁ × (d₂ ÷ d₁)^1.06
Riegel’s formula projects a finish time at a new distance from a recent result, assuming similar training and conditions.
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Frequently asked questions
How reliable is the prediction?
Good for nearby distances; the further the jump (e.g. 5K to marathon), the more it depends on endurance training.
Why the 1.06 exponent?
It reflects the slight slowdown as distance grows, fitted from real race data.
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