Race pace band and split planner
Plan your race-day splits: enter a goal time for a 5K, 10K, half marathon or marathon and get per-km split times for even pacing or a negative split.
| km | Elapsed | Pace |
|---|---|---|
| 1 | 5:43 | 5:43 |
| 2 | 11:26 | 5:43 |
| 3 | 17:09 | 5:43 |
| 4 | 22:52 | 5:43 |
| 5 | 28:35 | 5:43 |
| 6 | 34:18 | 5:43 |
| 7 | 40:01 | 5:43 |
| 8 | 45:44 | 5:43 |
| 9 | 51:27 | 5:43 |
| 10 | 57:10 | 5:43 |
| 11 | 1:02:51 | 5:40 |
| 12 | 1:08:31 | 5:40 |
| 13 | 1:14:10 | 5:40 |
| 14 | 1:19:50 | 5:40 |
| 15 | 1:25:30 | 5:40 |
| 16 | 1:31:09 | 5:40 |
| 17 | 1:36:49 | 5:40 |
| 18 | 1:42:28 | 5:40 |
| 19 | 1:48:08 | 5:40 |
| 20 | 1:53:47 | 5:40 |
| 21 | 1:59:27 | 5:40 |
| 21.1 | 2:00:00 | 5:40 |
Tip: screenshot this table for race day. In Bangkok, starting conservatively matters even more — it gets hotter as the sun comes up.
How it works
Enter a distance and goal time, then choose a strategy. Even pace runs every km at the same pace. A negative split runs the second half slightly faster — 1–3% — which is how most personal bests are run.
The planner keeps your total time exactly on goal and shows elapsed time at each km so you can check yourself on the course.
In Bangkok, races start in the dark and get hotter after sunrise, so a conservative first half pays off even more than in cool cities. If it's a humid morning, adjust your goal with the heat pace calculator first.
FAQ
What is a negative split?
Running the second half of a race faster than the first. It saves energy early and usually produces a faster overall time than starting fast and fading.
How much faster should the second half be?
Only slightly: about 1–3%. In a half marathon targeting 2:00, a 2% negative split is roughly 5:45/km then 5:38/km.
What pace do I need for a sub-4 marathon?
About 5:41 per km on average. With a 1% negative split, start around 5:43/km and finish around 5:40/km.
Results are estimates for planning training, not medical advice.