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Race Time Predictor
Use your recent race results to predict your potential performance at other distances.
Recent Performance
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About the Riegel formula
Predictions use the Riegel formula: T₂ = T₁ × (D₂/D₁)^1.06, a widely-used model developed by researcher Peter Riegel. The exponent 1.06 accounts for the natural slowdown over longer distances due to aerobic fatigue. Predictions are most accurate when your input race distance is within 2-3x of the target distance.