How it works
Enter any two of distance, time and pace to get the third. Pace is time per mile or kilometer; speed is the inverse, distance per hour.
The race table projects finish times if you held exactly this pace. In practice most runners slow over longer distances, so prediction formulas like Riegel's add a few percent per doubling of distance.
Use it to set training paces, plan a race-day target or check your treadmill speed. Results are estimates, not medical advice.
Formula
Pace = time ÷ distance · Time = pace × distance · Distance = time ÷ pace
Questions people ask
How do I convert pace to speed?
Divide 60 by your pace in minutes. An 8:00 per mile pace is 60 ÷ 8 = 7.5 mph; a 5:00 per km pace is 12 km/h.
What pace do I need for a sub-4-hour marathon?
About 9:09 per mile or 5:41 per kilometer, held for the full 26.2 miles (42.195 km).
How long is a half marathon?
13.1094 miles or 21.0975 kilometers, exactly half the 42.195 km marathon distance.