Marathon Pace Calculator — Target Time to Splits
Enter your target marathon finish time and see the required pace per kilometer and per mile, plus every 5 km split from 5 km to the finish. Pick even splits or a negative split — the calculator does the math.
Split checkpoints
| Checkpoint | Split | Cumulative |
|---|---|---|
| 5.0 km | 24:53 | 24:53 |
| 10.0 km | 24:53 | 49:46 |
| 15.0 km | 24:53 | 1:14:39 |
| 20.0 km | 24:53 | 1:39:32 |
| 25.0 km | 24:53 | 2:04:25 |
| 30.0 km | 24:53 | 2:29:18 |
| 35.0 km | 24:53 | 2:54:11 |
| 40.0 km | 24:53 | 3:19:05 |
| 42.2 km | 10:55 | 3:29:60 |
How the marathon pace calculator works
A marathon is 42.195 kilometers or 26.2188 miles. Your target pace is simply target time ÷ distance, but the splits matter more than the average pace because a 2 percent positive split (second half slower than first) is the difference between hitting a time and missing it by several minutes.
Even splits are the conservative option: every 5 km is run at exactly the same pace, so you cross 21.1 km at exactly half your target time. Negative splits run the second half slightly faster than the first — the classic approach for disciplined marathoners, especially when the course is flat and the weather is cool.
The calculator generates both sets of splits. Use even splits as your ceiling on race day: if you are above the target pace in the first half you are running too fast and you will pay for it in the final 10 km.
Pace per km = target time ÷ 42.195 · Pace per mile = target time ÷ 26.2188 · Negative split: first half 1% slower, second half 1% faster
Frequently asked questions
Should I aim for even splits or a negative split?
Negative splits are optimal physiologically and give you a buffer if the day goes badly. Even splits are what most runners achieve at best, and they work well when the course is flat and the weather cool. The worst strategy is positive splits — going out fast hoping to bank time — which produces slower finishes in almost every marathon study.
How much faster should my second half be for a negative split?
About 1 to 2 percent faster. For a 3:30 target, that's roughly 1 to 2 minutes faster in the second half. More aggressive negative splits (3 percent or more) are rarely achievable because the first half is already slow enough that you are not running at marathon pace.
Does this work for the half marathon or 10 km?
Yes — the same math applies to any distance. For a half marathon, divide your target time by 21.0975 km or 13.1094 miles. For a 10 km, divide by 10 or by 6.2137 miles. The negative split advice holds for distances over about 10 km.
How do I pace for hills?
Not by raw pace. On a hilly course, use perceived effort or heart rate instead of pace for the climbs, then return to goal pace on the descents and flats. Trying to hold marathon pace up a climb will cost you 30 to 60 seconds later for every minute you gained on the hill.
Cora writes your pacing plan
The calculator gives you splits. CoreRise goes further: tell Cora your goal time and she will build a 12 to 20 week plan with tempo runs at goal pace, long runs with goal-pace finishes, and a two-week taper — all adjusted to what your training files actually show you can hold.