Work out marathon finish prediction instantly with clear inputs, formula shown and shareable results.
This is Riegel's formula, t2 = t1 x (d2 / d1) ^ 1.06, where the exponent above one encodes the fact that pace inevitably drops as distance grows. Riegel is accurate within a few percent for distances within about a factor of four, but it assumes marathon-specific endurance you may not yet have trained.
Riegel prediction
t2 = t1 x (d2 / d1) ^ 1.06
Required pace
pace = predicted time / target distance
t2 = t1 x (d2 / d1) ^ 1.06. This is Riegel's formula, t2 = t1 x (d2 / d1) ^ 1.06, where the exponent above one encodes the fact that pace inevitably drops as distance grows.
Riegel is accurate within a few percent for distances within about a factor of four, but it assumes marathon-specific endurance you may not yet have trained.
Enter distance you have raced, time for that distance, target race distance. The defaults shown are a realistic worked example — swap in your own figures to get a result you can use.