How it's calculated
Pace, time and distance are tied together by one relationship: time = pace × distance. Give the calculator any two and it works out the third:
- Find pace: pick a race (or enter a distance) and your finish time.
- Find finish time: pick a distance and the pace you plan to hold.
- Find distance: enter how long you ran and your average pace.
It then shows pace per mile and per kilometer, average speed, an even-pace splits table and what the same pace would mean over other race distances.
The formula
- Pace = time ÷ distance (seconds per mile or per km)
- Finish time = pace × distance
- Distance = time ÷ pace
- Speed = distance ÷ time (mph or km/h)
- Split n (even pace) = elapsed time at n miles or km = pace × n; the last split is shorter when the distance isn't a whole number.
Race distances: a marathon is 26 miles 385 yards (42.195 km) and a half marathon is exactly half that, 21.0975 km, as World Athletics defines them.World Athletics A mile is 1,609.344 meters exactly.NIST
Worked example
A 5K in 25 minutes is a pace of 8:03 /mi, or 5:00 /km, an average speed of 7.46 mph.
Holding 8:00 per mile for a full marathon would finish in 3:29:45.
Pace per kilometer: 5:41 HALF MARATHON IN 2:00:00
Assumptions and limitations
- Even pace. Splits assume you run every mile or kilometer at the same speed. Real races rarely go that way, because of hills, wind, crowds and fatigue.
- Not a race predictor. The "race finish times at this pace" table is straight arithmetic at the same average pace. It is not a prediction of what you could run at another distance.
- Measured distance. If your watch or app records a slightly different distance from the official course, its pace will differ from the one calculated here.
- Times are rounded to the nearest second for display.
For heart-rate-based training, try the heart rate zone calculator.