Tool · Pace & time
Race splits calculator
Enter your distance and goal time: RunMorph works out your target pace and your splits mile by mile, from the start line to the finish. Choose an even effort or a negative split, then print your pace chart to hold your rhythm on race day without going out too fast.
| Mile | Elapsed time | Pace for that mile |
|---|---|---|
| 1 mi | 8:01 | 8:01 /mi |
| 2 mi | 16:01 | 8:01 /mi |
| 3 mi | 24:02 | 8:01 /mi |
| 4 mi | 32:02 | 8:01 /mi |
| 5 mi | 40:03 | 8:01 /mi |
| 6 mi * | 48:03 | 8:01 /mi |
| 7 mi | 56:04 | 8:01 /mi |
| 8 mi | 1:04:05 | 8:01 /mi |
| 9 mi | 1:12:05 | 8:01 /mi |
| 10 mi | 1:20:06 | 8:01 /mi |
| 11 mi | 1:28:06 | 8:01 /mi |
| 12 mi | 1:36:07 | 8:01 /mi |
| 13 mi * | 1:44:07 | 8:01 /mi |
| 14 mi | 1:52:08 | 8:01 /mi |
| 15 mi | 2:00:09 | 8:01 /mi |
| 16 mi | 2:08:09 | 8:01 /mi |
| 17 mi | 2:16:10 | 8:01 /mi |
| 18 mi * | 2:24:10 | 8:01 /mi |
| 19 mi | 2:32:11 | 8:01 /mi |
| 20 mi | 2:40:11 | 8:01 /mi |
| 21 mi | 2:48:12 | 8:01 /mi |
| 22 mi * | 2:56:13 | 8:01 /mi |
| 23 mi | 3:04:13 | 8:01 /mi |
| 24 mi | 3:12:14 | 8:01 /mi |
| 25 mi | 3:20:14 | 8:01 /mi |
| 26 mi | 3:28:15 | 8:01 /mi |
| 26.22 mi (finish) | 3:30:00 | 8:01 /mi |
Highlighted rows marked with an asterisk are the key pacing checkpoints for this distance; the finish row gives your final time. Print this table or write your splits on your wrist to hold your pace on race day.
How to calculate your splits
A split is the cumulative time you should see on your watch at a given point on the course to stay on track for your goal. The math rests on a single idea: turn your goal time into a target pace, then project it onto every mile.
1. Your target pace (even split)
Divide the goal time by the distance:
Then the cumulative split at mile k is simply:
Worked example: a 3:30 marathon means 12,600 seconds over 26.219 miles. The target pace is 12,600 ÷ 26.219 ≈ 480.6 s/mi, about 8:01/mi. Your split at mile 10 is then 480.6 × 10 ≈ 4,806 s, or 1:20:06, halfway (13.1 mi) comes up around 1:45, and the finish at 26.2 miles brings you in right on 3:30.
2. The negative split option
A negative split means running the second half a little faster than the first while keeping the same finish time. If you choose a gap g (in s/mi), the calculator applies even pace + g/2 to the first half and even pace − g/2 to the second. The average stays at the even pace, so your goal time holds, but you start more cautiously, which protects the end of your race.
Example: for the same 3:30, a gap of 10 s/mi gives ~8:06/mi for the first half and ~7:56/mi for the second. You go through halfway a few seconds slower, then pick it up to finish on time.
Marathon benchmarks: pace and key splits
For the most common marathon goals, here is the target pace (even split) and your splits at the key checkpoints: halfway (13.1 mi), mile 20 (where the wall usually hits) and the finish. Use the calculator above for the full mile-by-mile breakdown and for other distances.
| Goal | Target pace | Halfway (13.1 mi) | Mile 20 | Finish (26.2 mi) |
|---|---|---|---|---|
| 3:00:00 | 6:52 /mi | 1:30:00 | 2:17:18 | 3:00:00 |
| 3:30:00 | 8:01 /mi | 1:45:00 | 2:40:11 | 3:30:00 |
| 4:00:00 | 9:09 /mi | 2:00:00 | 3:03:05 | 4:00:00 |
| 4:30:00 | 10:18 /mi | 2:15:00 | 3:25:58 | 4:30:00 |
| 5:00:00 | 11:27 /mi | 2:30:00 | 3:48:51 | 5:00:00 |
These benchmarks assume an even pace over the whole course. On race day, a slight negative split (starting 5 to 10 s/mi more cautiously) often locks in a better finish time.
Frequently asked questions
What are splits in running?
A split is the cumulative time you should reach at a specific point on the course (at mile 10, say) to stay on pace for your final goal. It’s the checkpoint that tells you, mid-race, whether you’re on schedule, ahead or behind. They’re also called intermediate times.
How do I calculate my splits for a goal time?
Start from your goal time and the distance. Your target pace (in seconds per mile) equals the total time divided by the distance in miles. The split at mile k is then simply that pace multiplied by k. Example: a 3:30 marathon (12,600 s over 26.219 mi) gives a pace of about 481 s/mi, roughly 8:01/mi, so a split at mile 10 around 1:20:06.
Even split or negative split: which should I choose?
An even split (the same pace from start to finish) is the simplest and often the most effective, especially over 5K and 10K. A negative split means running the second half a little faster than the first: it makes pacing safer over the half and the marathon, where going out too fast costs you dearly late in the race. In the calculator, the negative split option keeps the same finish time but spreads the effort so you start slightly more cautiously.
Why not go out as fast as possible?
Because energy spent too early doesn’t come back. Going out 15 to 25 seconds per mile too fast in a marathon drains your glycogen stores and triggers the famous “wall” around mile 20, where your pace collapses. Holding steady (or slightly faster) splits protects the end of your race and almost always gives a better overall time.
How do I use this chart on race day?
Print it or copy a few key checkpoints onto a pace band or the back of your hand: halfway and, for a marathon, miles 6, 13, 18 and 22. At each marker, compare your watch with the planned split. Keep in mind that official mile markers never line up perfectly with GPS: trust the course markers.
Turn your goal time into a training plan
RunMorph builds a session-by-session plan, periodized all the way to race day, to get you holding these splits when it counts.
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