half marathon pace and finish time calculator
The half marathon is 21097.5 metres — 21.10 km, or 13.109 miles. Enter a pace and this gives the finish time, or work backwards from a target. Exactly half the marathon distance: 21.0975 km.
Finish time
1:58:09
- Speed
- 10.714
- Pace per mile
- 9:01
- Pace per kilometre
- 5:36
- Pace needed for the target time
- 0:00
- Halfway split
- 0:59:04
- Quarter split
- 0:29:32
- Pace per 400 m lap
- 2:14
- Track laps
- 52.74
- Speed in metres per second
- 2.976
Show the working
- Pace, minutes per km = 5.6
- Plus seconds = 0
- Or a target time, hours = 0
- Target minutes = 0
- distance_m = 21097.5 = 21 097.5
- distance_km = 21 097.5 / 1000 = 21.0975
- Pace per kilometre = 5.6 * 60 + 0 = 336
- Finish time = 336 * 21.0975 = 7088.76
- Speed = 336 > 0 ? 3600 / 336 : 0 = 10.7143
- Speed in metres per second = 10.7143 / 3.6 = 2.976 19
- Pace per mile = 336 * 1.609344 = 540.74
- target_seconds = 0 * 3600 + 0 * 60 = 0
- Pace needed for the target time = 21.0975 > 0 && 0 > 0 ? 0 / 21.0975 : 0 = 0
- Halfway split = 7088.76 / 2 = 3544.38
- Quarter split = 7088.76 / 4 = 1772.19
- Pace per 400 m lap = 336 * 0.4 = 134.4
- Track laps = 21 097.5 / 400 = 52.7438
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
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The formula
- finish time = pace per km x distance in km
- pace per mile = pace per km x 1.609344
- speed in km/h = 3600 / pace in seconds per km
Splits assume an even pace. Most runners are better served by starting slightly slower than target and finishing faster.
The mile is exactly 1609.344 m, so the pace conversion here is exact rather than rounded.
Exactly half the marathon distance: 21.0975 km.
Finish times for the half marathon
| Pace per km | Pace per mile | Finish time |
|---|---|---|
| 3:30 | 5:38 | 1:13:50 |
| 4:00 | 6:26 | 1:24:23 |
| 4:30 | 7:15 | 1:34:56 |
| 5:00 | 8:03 | 1:45:29 |
| 5:30 | 8:51 | 1:56:02 |
| 6:00 | 9:39 | 2:06:35 |
| 6:30 | 10:28 | 2:17:08 |
| 7:00 | 11:16 | 2:27:41 |
| 8:00 | 12:52 | 2:48:47 |
Frequently asked
How far is the half marathon?
21097.5 metres, which is 21.10 km or 13.109 miles.
What pace do I need for a specific time?
Divide the target time by the distance in kilometres. The calculator does it in the "pace needed" row.