How this calculator works
Pace is time per unit of distance, so the same finish time gives a different number on every course. This page divides the finish time by the race distance in kilometres to get seconds per kilometre, then multiplies by 1.609344 for seconds per mile. Working the other way, it multiplies the pace by the distance. The split table shows even pacing with no fade and no fast finish, which is the simplest target to memorise on race day.
Formula
Pace (seconds per km) = finish time in seconds / race distance in km. Finish time = pace x distance in km. Pace per mile = pace per kilometre x 1.609344. Average speed = distance / time.
Worked example
A 3:30:00 marathon is 12,600 seconds over 42.195 km, so the pace is 12,600 / 42.195 = 298.6 seconds per kilometre, or 4:59. The mile pace is 298.6 x 1.609344 = 480.6 seconds, or 8:01. The first 5 km split falls at 5 x 298.6 = 1,493 seconds, or 24:53. Holding 5:00 per kilometre instead gives 300 x 42.195 = 12,658.5 seconds, or 3:30:59.
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Frequently asked questions
Should I run even splits?
Even or slightly negative splits are the most efficient way to cover a distance, and the table gives that baseline. Many runners still start a little slower and finish faster, which protects against the late-race slowdown that a fast start usually causes.
Does the pace account for the course?
No. This is a flat, still-air pace. Hills, heat, wind and crowded aid stations all add time. Adjust the target on the day and treat the even-split table as a neutral reference.
Why is the mile pace not simply the kilometre pace times 1.6?
1.6 is a rounded approximation. The international mile is exactly 1,609.344 metres, so 1.609344 is the exact factor. The difference is small but grows over a marathon.
What is a good marathon pace?
It depends on your recent race times and training. A common guide is that marathon pace is roughly 15 to 30 seconds per kilometre slower than half marathon pace, but the best estimate comes from a recent race and a progressive long run at goal pace.