You have entered a half marathon. Somewhere around two in the morning, the question arrives: how long is this actually going to take? The honest answer is anywhere between ninety minutes and four hours, which is roughly as useful as being told that a train to Manchester takes between one hour and a day.
So here are the actual numbers. Your finish time is decided almost entirely by the pace you can hold while bored and mildly miserable at mile nine, not the pace you hit on a good Tuesday when the wind was behind you.
The short answer
The most widely quoted figures come from RunRepeat, which analysed 107.9 million race results from more than 70,000 events between 1986 and 2018. Average half marathon time for men: 1:55:26. For women: 2:11:57.
Read the small print, though. That dataset is made of race results, so it is weighted towards people who enter a lot of races, and serial racers are quicker than someone who signed up in January because their sister-in-law did. If your first half lands north of those averages, you have joined a very large and mostly unrecorded majority.
A more honest framing: most first-time half marathoners who trained sensibly finish somewhere between 2:10 and 2:50. Plenty finish later than that. The medal is identical.
The pace table
A half marathon is 13.1 miles, or 21.1km. That is the whole of the maths, and here is what it turns into.
| Pace per mile | Pace per km | Finish time |
|---|---|---|
| 8:00 | 4:58 | 1:44:52 |
| 9:00 | 5:35 | 1:57:59 |
| 10:00 | 6:13 | 2:11:05 |
| 11:00 | 6:50 | 2:24:12 |
| 12:00 | 7:27 | 2:37:18 |
| 13:00 | 8:04 | 2:50:25 |
| 14:00 | 8:42 | 3:03:31 |
| 15:00 | 9:19 | 3:16:38 |
| 16:00 | 9:56 | 3:29:45 |
| 17:00 | 10:34 | 3:42:51 |
Reading it backwards
If you have a number in your head instead of a pace, flip it. Two hours needs 9:09 per mile, or 5:41 per kilometre. Two thirty needs 11:26 per mile, or 7:06 per km. Three hours needs 13:43 per mile, which is 8:31 per km and comfortably slower than most people walk uphill in a hurry.
Look at the gap between those. Thirty minutes of finish time is worth barely two minutes a mile. This is why the clock feels so brutal on the day — tiny pace slippage, multiplied by thirteen.
What actually decides your time
Your long run pace, not your 5K pace
Nearly everybody predicts their half off a short, sharp effort they once did. It does not translate. The pace that decides your half is the one you can hold for ninety minutes without your form quietly falling apart. If your longest run averaged 11:30 a mile, race day is 11:00 to 11:15, not 9:45 because you feel bold.
The first three miles you did not mean to run that fast
The single biggest tax on an ordinary finish time. You are fresh, the field is dense, someone is playing music, and you go through mile two forty seconds a mile quicker than planned. You pay that back after mile nine at an exchange rate that would embarrass a Heathrow bureau de change.
The elevation profile you glanced at once
A hundred metres of climb spread thinly across thirteen miles is barely noticeable. The same hundred metres stacked into one lump at mile eleven will cost you minutes and possibly your sense of humour. Check where the climbing lives, not just how much there is.
The four minutes nobody budgets for
Start pen shuffle. A water station where you slow to a walk, because drinking while running is a skill you never practised. One toilet queue. A gel wrapper you cannot open with cold hands. Together it is routinely three to five minutes. Budget it rather than being surprised by it.
Walking does not ruin your time
There is a persistent idea that walking any part of a half converts the result into an asterisk. It does not. A steady run-walk pattern held from the start — nine running, one walking, repeated — beats running the first eight miles heroically and shuffling the last five in quiet despair. Ask anyone who has done both, usually in the same year.
The trick is to start the walk breaks before you need them. Once you are walking because your legs have made the decision for you, you are managing damage rather than pacing.
Will they close the course on you?
This is the fear underneath the question, and it is worth answering directly. Great Run, who put on the Great North Run and most of the big Great series events, state that unless a cut-off is specified on the event page there is no cut-off at all. They run a sweep vehicle at 17-minute-mile pace, and if it catches you, you are asked to continue on the pavement rather than being removed. Their finish area stays open until the last entrant has crossed.
Seventeen-minute miles is a 3:42 half. Other organisers are stricter, and a four-hour limit is common on city courses where roads have to reopen, so read the event page rather than assuming. We have written a longer piece on UK races with the most generous cut-off times if the clock is the thing keeping you from entering.
Two hours is a long time to be wearing the wrong thing
Kit does not make you faster. It stops you getting slower for stupid reasons. The longer you are out there, the more time a bad seam has to do its work — a 2:45 half is nearly an hour more rubbing than a 1:50 half, on the same course.
Shorts that stay put matter most, so the Suffer running shorts are the thing to get right first. Blister running socks earn their name around mile ten, when small friction becomes a large opinion. And if the sun is doing its thing, the Brow Mop cap keeps sweat out of your eyes while you are still trying to read mile markers. The rest of the kit is there when you want it. None of it takes a minute off. All of it stops the last five miles being about something other than running.
Common questions
Is a 2:30 half marathon a good time?
Yes. It is slower than the quoted averages, which come from habitual racers, and quicker than a great many people finishing halves in Britain every weekend. A 2:30 is 11:26 per mile held for two and a half hours, which is a hard thing to do.
How long does it take to train for a half marathon?
If you can already run for 30 minutes without stopping, twelve to sixteen weeks is a sensible runway. From a standing start, closer to five or six months, because the limiting factor is tendons and connective tissue adapting, and those take longer than your lungs do.
Can you walk a half marathon?
At many events, yes, though it depends entirely on the organiser. A brisk walk is roughly 15 to 17 minutes a mile, which puts you at 3:16 to 3:43, so a race with a four-hour limit or no limit at all is fine and a three-hour limit is not. Check the event page before you enter, not after.
Do I need to run 13 miles before race day?
Most plans for slower runners cap the long run around 10 to 12 miles and let the taper and the crowd cover the rest. Running the full distance in training costs more recovery than it buys confidence, though plenty do it anyway for peace of mind.
Will I be slower than my training pace on the day?
Usually faster, by a small amount. Fresh legs, a taper and other people to follow are worth about fifteen to thirty seconds a mile — not the full minute people assume, and only if you did not spend it all in the first two miles.
Related reading
Our half marathon training plan for slow runners is built around exactly these paces. For picking an event, try the best UK half marathons for ordinary runners. And if caring about the clock has got its hooks in you, read in defence of the 35 minute 5K, then go for a run without a watch.
Suffer every mile. Still no medals. The clock is only ever a description of one Sunday, and never a description of you.