Marathon pace calculator

Quick answer: a 4:30:00 marathon needs 10:18 per mile or 6:24 per kilometre (5.83 mph). The halfway mark comes at 2:15:00 and 20 miles at 3:25:58.

How to use it

With Find pace, the marathon distance is already set: type your goal, such as 3:45 or 4:30:00, and read the pace in both units, the treadmill speed and every mile split. With Find time, enter a pace instead, which is useful when you know what your long runs feel like. 10:00 per mile holds up to a 4:22:11 finish; 9:00 per mile gives 3:55:58; 6:00 per km gives 4:13:10.

Worked example

A marathon is 42.195 km, which is 26.2188 miles. A 4:30:00 goal is 16,200 seconds. 16,200 / 26.2188 = 617.9 seconds per mile, so 10:18. 16,200 / 42.195 = 383.9 seconds per km, so 6:24. As a speed, 26.2188 miles in 4.5 hours is 5.83 mph (9.38 km/h).

Why your watch will disagree

Courses are measured along the shortest legal line, and almost nobody runs it, so GPS usually shows a little more than 26.2 miles at the finish. If you pace by the watch alone you will be a few seconds per mile slow by the end. Many runners aim a few seconds per mile under their target pace, or follow the course mile markers instead.

What the other rows mean

Under the splits, the tool shows the same effort at shorter races, using the Riegel formula backwards. A 4:30:00 marathon lines up with about 2:09:30 for the half, 58:42 for the 10K and 28:09 for the 5K. If your recent 10K is a lot slower than that, the goal is ambitious; if it is faster, you may have room to aim higher.

Next: every checkpoint on the marathon pace chart, a printable pace band, or a negative-split plan on the split calculator.

Formula and examples checked 7 October 2026. Found a problem? Tell us.

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