Marathon Time Predictor
Predict race times across distances.
Uses Riegel's formula (T2 = T1 × (D2/D1)^1.06). Most accurate for race distances close to your input. Marathon predictions from a 5K tend to be optimistic if you have not trained for distance.
About
Run one race well and you can guess the others. Type a recent race time and the tool predicts your finish at every common distance, from a mile to a marathon. Uses Riegel's formula, the same one most coaches reach for.
How to use
- Pick the distance you ran.
- Enter your time.
- Read predicted times for every other common distance.
FAQ
How accurate is the prediction?+
Most accurate for distances close to your input. A 10K predicts a half marathon well; predicting a marathon from a 5K assumes you've trained for the distance. If you haven't run more than 20 miles a week, the marathon prediction is optimistic.
Where does the formula come from?+
Pete Riegel published it in 1977. The 1.06 exponent comes from observing real race results. It's not magic but it's solid.