Calculate running pace and predict race times
Calculate pace per km or mile from a distance and time, and predict finish times for other distances using the Riegel formula.
Race predictions use Riegel's formula, which assumes even training and pacing across distances. Real race times vary with terrain, weather, and fitness on the day.
Enter the distance you ran (km or miles) and the time it took, in hours, minutes, and seconds.
Your pace per kilometre and per mile is calculated instantly.
See predicted finish times for 5K, 10K, half marathon, and marathon, based on your current pace and the Riegel formula.
Frequently asked
How are race time predictions calculated?
Using Riegel's formula (T2 = T1 * (D2/D1)^1.06), a widely-used endurance running model that accounts for pace naturally slowing over longer distances.
How accurate are the predictions?
They assume similar training and pacing across distances, so they're a reasonable ballpark, not a guarantee. Terrain, weather, and fitness on race day all affect the real result.
Is this medical advice?
No. This is a general estimate for informational purposes only, not medical advice. Talk to a healthcare provider or certified trainer before changing your training or diet.