โฝ Sports
Race Time Predictor
Riegel predicted time equals the known time multiplied by the ratio of distances raised to the power 1.06. The exponent captures fatigue: the same effort cannot be held across a longer distance at the same pace.
How it works
Known distance
Known time โ hours
Known time โ minutes
Fatigue exponent
5 km
10 km
Half marathon
Marathon
Note
Frequently asked questions
How do I use the Race Time Predictor?
Fill in the fields above โ the result recalculates instantly as you type. Everything runs in your browser, so the values you enter are never collected or stored.
Is this calculator free?
Yes. It is completely free, requires no account, and works on phones, tablets and desktops.