Half marathon pace:
finish time = pace × 21.0975
Match a per-kilometre pace to a half marathon finish time, work out the pace for your goal, and avoid the decimal-minutes slip.
Calcylator Editorial Team
Updated · 5 min read
Half marathon pace: what to run for your goal time
A half marathon is 21.0975 kilometres, so a steady pace of 5:30 per kilometre finishes in about 1 hour 56 minutes and 2 seconds. To find the pace for any goal, divide the goal time in minutes by 21.0975. A 1 hour 45 goal needs about 4:59 per kilometre.
- pace:
- minutes per kilometre
- minutes:
- total time in minutes
- distance:
- 21.0975 km for a half marathon
Goal time
1 h 45 min = 105 min
Distance
21.0975 km
Divide
105 ÷ 21.0975
Pace
4.98 min/km
The decimal 0.98 minutes is 0.98 × 60 = 59 seconds, so the pace is 4:59 per km.
Half marathon pace chart
| Pace per km | Finish time | 5 km split |
|---|---|---|
| 4:30 | 1:34:56 | 22:30 |
| 5:00 | 1:45:29 | 25:00 |
| 5:30 | 1:56:02 | 27:30 |
| 6:00 | 2:06:35 | 30:00 |
| 6:30 | 2:17:08 | 32:30 |
| 7:00 | 2:27:41 | 35:00 |
| 7:30 | 2:38:14 | 37:30 |
| 8:00 | 2:48:47 | 40:00 |
Finish times are rounded to the nearest second. In a real race the first and last stretches rarely match your average exactly, so treat the chart as a target rather than a promise.
A second worked example: a pace of 6:15 per km is 6.25 minutes, and 6.25 × 21.0975 = 131.86 minutes, which is 2 hours 11 minutes and 52 seconds. Runners who are new to the distance often land in this range, and it leaves comfortable room for a walk break at a water station.
Goal time to pace per kilometre
| Goal time | Pace per km |
|---|---|
| 1:30:00 | 4:16 |
| 1:45:00 | 4:59 |
| 2:00:00 | 5:41 |
| 2:15:00 | 6:24 |
| 2:30:00 | 7:07 |
Notice that shaving 15 minutes off a two-hour goal needs only about 42 seconds per kilometre. That is a useful way to explain to yourself why a small improvement in training can move your finish time a lot.
If you have a recent 10 km time, use it for a first guess. A 10 km in 55:00 is exactly 5:30 per km. Because a half marathon is twice as long, most runners settle a little slower than their 10 km pace, so aim for a goal pace a few seconds per kilometre above that and see how the long training runs feel.
The same arithmetic works in training. A 16 km long run at 6:15 per km takes 16 × 6.25 = 100 minutes, so you can plan your fuel, route and start time before you leave the house.
The decimal minutes trap
The calculator shows pace as decimal minutes, so 5.50 means five and a half minutes, which is 5:30, not 5:50. To convert, multiply the decimal part by 60. A result of 5.69 is 5 minutes and 0.69 × 60 = 41 seconds, so 5:41.
Using the pace on race day
- Set your watch to show current lap pace and average pace so you can spot early drift.
- Check each 5 km split against the chart. At 5:30 per km you should pass 5 km at 27:30 and 10 km at 55:00.
- Start at or slightly slower than goal pace; a fast first 5 km usually costs more than it saves later.
- If you track miles, remember that 5:30 per km is about 8:51 per mile, because one mile is 1.609344 km.
Common mistakes
- Using 21 km instead of 21.0975 km. This understates a 5:30 pace finish by about 32 seconds.
- Reading decimal minutes as minutes and seconds.
- Planning from your best 5 km pace, which you cannot hold for four times the distance.
- Ignoring hills, heat and crowded starts when choosing a goal.
Common questions
What pace do I need for a 2 hour half marathon?
You need about 5:41 per kilometre. Divide 120 minutes by 21.0975 km to get 5.69 minutes per km, and 0.69 of a minute is about 41 seconds. In miles, that is roughly 9:09 per mile. Start steadily and avoid a fast first few kilometres.
How far is a half marathon in km?
A half marathon is 21.0975 kilometres, which is exactly half of a marathon at 42.195 km. In miles it is about 13.1. Rounding to 21 km makes a pace-based finish time about half a minute too short, so use 21.0975 when planning.
How do I calculate half marathon finish time from pace?
Multiply the pace in minutes per kilometre by 21.0975. For example, 5:30 per km is 5.5 minutes, and 5.5 × 21.0975 is about 116.04 minutes, or 1 hour 56 minutes and 2 seconds. Convert any decimal part to seconds by multiplying by 60.
What is a 5:30 per km pace in miles?
It is about 8:51 per mile. Multiply 5.5 minutes by 1.609344 to get 8.85 minutes, and 0.85 of a minute is about 51 seconds. Use the same factor to switch any kilometre pace to a mile pace.
Should I run even splits in a half marathon?
Even or slightly negative splits are a sensible plan for most runners, because starting too fast tends to cause a late slowdown. Use the chart to set each 5 km target, but adjust for hills, weather and how you feel on the day.
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