Race Time Predictor
Predict your time at a new distance from a recent race result.
Result
Predicted time
45:52
At a pace of
4:35 /km
What it means
This uses Pete Riegel's endurance formula — T₂ = T₁ × (D₂ ÷ D₁)^1.06 — to predict your time over a new distance from a recent race result. The 1.06 exponent accounts for the fact that we slow down slightly as distance grows.
It's most accurate when the two distances are reasonably close and you're aerobically trained for the longer one. Predicting a marathon off a 5 k will flatter you if you haven't done the long-run work.
Let the app do this for you
Ride & Run Lab calculates all of this automatically from your real rides — plus an AI coach, form & fitness tracking and segments. $5/month.