HALF MARATHON SPLIT CALCULATOR · 21.0975 KM
Half marathon split calculator
Enter your goal to get a split for every mile, kilometre or 5 km mat, ending exactly on your finish time. A 2:00:00 half marathon at even pace is 9:09 per mile (5:41 per km): 5 km in 0:28:26, 10 km in 0:56:53, mile 13 at 1:59:00, and the last 1.0975 km from the 20 km mat takes 6:15.
Prints a 40 × 240 mm strip. Print at 100% (Actual size), then check the 50 mm ruler.
Even, negative and positive splits for 2:00:00
| Checkpoint | Even | Negative | Positive |
|---|---|---|---|
| 5 km | 0:28:26 | 0:28:52 | 0:28:00 |
| 10 km | 0:56:53 | 0:57:29 | 0:56:17 |
| 15 km | 1:25:19 | 1:25:49 | 1:24:50 |
| 20 km | 1:53:45 | 1:53:53 | 1:53:38 |
| Half marathon (21.0975 km) | 2:00:00 | 2:00:00 | 2:00:00 |
All three plans finish at 2:00:00; only the checkpoint times in between change.
Even splits, every 5 km
| Checkpoint | Segment | Pace /km | Elapsed |
|---|---|---|---|
| 5 km | 0:28:26 | 5:41 | 0:28:26 |
| 10 km | 0:28:27 | 5:41 | 0:56:53 |
| 15 km | 0:28:26 | 5:41 | 1:25:19 |
| 20 km | 0:28:26 | 5:41 | 1:53:45 |
| Half marathon (21.0975 km) | 0:06:15 | 5:42 | 2:00:00 |
The 5 splits add up to exactly 2:00:00. The final 1.0975 km is run at 5:42 per km. Halfway (10.5488 km) comes at 1:00:00.
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Print at 100% (Actual size) with headers and footers off. The strip is 40 × 240 mm. Measure the 50 mm ruler before cutting; if it is not 50 mm, your printer rescaled the page. Tape it loosely around your wrist.
RACE PACE PLANNER
Half marathon · 2:00:00
Even splits · Continuous
| km | Time |
|---|---|
| 5 | 0:28:26 |
| 10 | 0:56:53 |
| 15 | 1:25:19 |
| 20 | 1:53:45 |
| 21.0975 | 2:00:00 |
Elapsed time includes stops. Targets, not predictions. racepaceplanner.com
Overlap and tape here
Three ways to pace the full 21.0975 km
We checked the top 5 US and UK results for “half marathon split calculator” on 24 September 2026. Every split table among them assumed even pacing, and one calculator uses 21.1 km, so 5:00 per km shows 1:45:30 instead of 1:45:29. None lists the 5, 10, 15 and 20 km checkpoints on their own or times the stretch after mile 13 separately. The calculator above does both, for even, negative and positive pacing side by side.
What is a good split for a half marathon?
Even or slightly negative is the usual target. The 2025 review cited below reports that most record-breaking performances follow an even or slightly negative split, and that recreational runners tend to run positive splits, slowing in the second half. This site's negative preset turns a 2:00:00 goal into 1:00:36 for the first half and 0:59:24 for the second, a 72-second difference. Pick “Negative” in the calculator to see it for your own goal. For that two-hour goal on its own, the sub-2 half marathon page adds the treadmill setting and the 10K and 5K times that go with it.
How the splits are calculated
Even splits give each segment time in proportion to its length. Negative splits start 2% slower than average and speed up steadily to finish 2% faster; positive splits do the reverse. Every checkpoint is the exact elapsed time rounded to the nearest second, so the last split always matches your goal. The 2% is an illustrative preset chosen for this site. Hills, heat and wind are not modelled.
Sources
- World Athletics: half marathon: 13.1094 miles or 21.0975 km.
- NIST: unit conversion factors: 1 mile = 1.609344 km exactly.
- Grivas GV (2025), Frontiers in Physiology 16:1639816: review of negative-split pacing.
Last checked 17 October 2026.