Half marathon · 12 weeks · free

The 12-week half marathon training plan

Forty-eight runs, every one of them written out with a distance and a purpose. The long run climbs from 5 miles to 12, three cutback weeks are built in, and there is a protocol for what to do when you miss one — because you will.

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Is 12 weeks right for you?

Twelve weeks is the right block if you can run three miles continuously today. That is the entry test, and it is worth being honest about, because every problem in half-marathon training traces back to starting a block from a base that wasn't there.

If three miles is a stretch right now, you don't need a different half plan — you need eight more weeks before this one. The 12-week 10K beginner plan gets you to a six-mile long run, which makes week 1 here comfortable rather than alarming.

If you're already running 20+ miles a week with a long run over 8 miles, this plan will feel easy in the first month. Start at week 5.

The full plan, week by week

Four runs a week: two easy, one quality session, one long. The bar beside each week is that week drawn to scale, so you can see the long run take over.

easy runtempointervalslong run
Week1
Easy 3 · Tempo 3 · Easy 3 · Long 5
14mi this week
Week2
Easy 3 · Tempo 3 · Easy 3 · Long 6
15mi this week
Week3
Easy 3 · Tempo 4 · Easy 3 · Long 7
17mi this week
Week4
Easy 3 · Tempo 3 · Easy 3 · Long 5
Cutback week. Everything drops, including the long run. Skipping this is how week 7 becomes an injury.
14mi this week
Week5
Easy 3 · Tempo 4 · Easy 4 · Long 8
19mi this week
Week6
Easy 4 · Tempo 4 · Easy 4 · Long 9
21mi this week
Week7
Easy 3 · Tempo 4 · Easy 3 · Long 6
Cutback week.
16mi this week
Week8
Easy 4 · Intervals 5 · Easy 4 · Long 10
Double figures. The first long run that needs water and a plan for where you'll be at mile 8.
23mi this week
Week9
Easy 4 · Intervals 5 · Easy 4 · Long 11
24mi this week
Week10
Easy 4 · Tempo 4 · Easy 4 · Long 8
Last cutback before the peak.
20mi this week
Week11
Easy 4 · Intervals 5 · Easy 4 · Long 12
Peak week. Twelve is the longest run in the plan and it is deliberately not thirteen.
25mi this week
Week12
Easy 4 · Easy 3 · Easy 2 · Race 13.1
Taper. Mileage drops by roughly 40% and the intensity goes with it.
Racemi this week

Weekly mileage runs 14 → 15 → 17 → 14 → 19 → 21 → 16 → 23 → 24 → 20 → 25 → race. The bold weeks are cutbacks and they are not optional; there is a section below on why.

Run the four sessions on any four days that keep the long run on its own and leave at least one full rest day. The common arrangement is Tuesday tempo, Wednesday easy, Friday easy, Sunday long, but the specific days matter far less than not stacking the tempo and the long run back to back.

The long-run ladder: 5 miles to 12

5 mi
9 mi
12 mi
5 miWeek 1
the starting point
9 miWeek 6
past the halfway mark
12 miWeek 11
peak, and not 13.1

Three cutback weeks sit between these, which is why the line is a staircase and not a ramp.

The long run is the only session in this plan that cannot be substituted. Everything else exists to let you keep doing it.

It climbs five to twelve across eleven weeks with drops in weeks 4, 7 and 10. It tops out at twelve rather than thirteen for a specific reason: the last 1.1 miles cost more in recovery than they add in fitness, and race day supplies them for free. Almost every mainstream half plan makes the same call.

From week 8 onwards, treat the long run as a dress rehearsal. Same shoes, same breakfast, same fuel at the same intervals. By week 11 there should be nothing about race morning you haven't already tested.

The four run types and what each is for

Four sessions, four different jobs. Running all of them at the same effort is the most common way a plan produces fatigue instead of fitness.

Easy run

Most of the plan. Conversational, 90–120 seconds per mile slower than goal race pace. Its purpose is volume without damage, and running it too fast is the single most common reason a 12-week block ends early.

Tempo run

Twenty minutes at roughly 15–20 seconds per mile slower than your 10K pace, with a mile easy either side. It should feel "comfortably hard" — sustainable, but you would not want to hold a conversation.

Intervals

From week 8: 6 × 800m at 10K pace minus about 10 seconds per mile, with a 400m jog between. This is the only genuinely fast running in the plan and there is deliberately not much of it.

Long run

The point of the whole thing. Slow, deliberately — see the pace table below — and building from 5 miles to 12 with three cutbacks along the way.

What pace to run your long runs

"Conversational" is the standard advice and it is not actionable at mile nine. Here are numbers.

Your long runs belong 60 to 90 seconds per mile slower than your goal race pace. Find your goal finish time on the left and run the right-hand column.

Half marathon is 13.1 miles. Goal pace is the finish time divided by 13.1; the long-run range adds 60–90 seconds.
Goal finishGoal race paceRun your long runs at
2:3011:27 / mi12:30 – 13:00 / mi
2:1510:18 / mi11:20 – 11:50 / mi
2:009:09 / mi10:10 – 10:40 / mi
1:458:01 / mi9:00 – 9:30 / mi
1:306:52 / mi7:50 – 8:20 / mi

Two exceptions worth knowing. On the last three miles of the week-9 and week-11 long runs you can lift to goal pace if you feel good — that's a useful rehearsal for finishing tired. And on any long run in the heat, throw the numbers away and run by effort, because pace at 80°F is not the same work as pace at 50°F.

Cutback weeks, and why you don't skip them

Weeks 4, 7 and 10 go backwards. Mileage drops, the long run shortens, and the quality session gets easier. Every one of them will arrive in a week when you feel strong and would rather push on.

Push on and here is what happens: fitness is not built during hard weeks, it is built during the recovery after them. Training load accumulates faster than the body repairs, and three consecutive build weeks is roughly where that gap opens up for most recreational runners. The cutback is the repair window.

It also functions as an early-warning system. If you arrive at week 7 and a reduced week still feels hard, that is information — you are behind on sleep, under-eating, or accumulating an injury, and you have found out in week 7 rather than week 11.

The one legitimate modification: if you genuinely felt flat through weeks 5 and 6, make the cutback two weeks rather than one and repeat week 7. You will lose nothing and arrive at week 8 able to run it.

Race week and the taper

Week 12 drops your mileage by about 40% and drops the intensity with it. Four easy, three easy, two easy, then race.

The taper does not make you fitter. It removes fatigue so that the fitness you already have can show up, and it is almost impossible to overdo — runners far more often ruin a race by training through the last week than by resting too much.

Expect to feel terrible. Taper weeks come with phantom niggles, restless legs and the absolute conviction that you have lost all your fitness in nine days. This is so universal it has a name. It is not a signal and it requires no response.

Race morning: eat what you ate before your long runs, at the same interval. Arrive early enough that the queue for the toilets is a nuisance rather than a crisis. And run the first three miles slower than feels right — a half marathon is won or lost between miles 9 and 13, and what happens there was decided in the first three.

If you miss a week

Most plans pretend this won't happen. Over twelve weeks, with a job, it happens to almost everyone. Here is the protocol, and it is the part of this page worth screenshotting.

What you missedWhat to doEffect on race day
One weekRepeat the week you missed, then carry on. Everything shifts back seven days.None, if your race is flexible. If it isn't, you go in one week under-prepared — survivable.
Two weeksDrop back two weeks from where you were and rebuild. Do not rejoin at the week the calendar says.Change the goal from a time to a finish. The fitness is still there; the durability isn't.
Three or moreChange the race, not the plan. Restart from week 1, or from week 5 if you kept some running going.Compressing a block to hit a date is the single most reliable way to arrive injured.
Only the long runNever skip two long runs in a row. Miss one, keep the following week as written.Minimal. One missed long run costs very little; two in a row costs the ladder.

The rule underneath all four rows: never bridge a gap by doing extra. The instinct after a missed week is to add mileage to catch up, and it is precisely backwards — you are less adapted than the plan assumes, not more.

Print it or put it in your calendar

Forty-eight runs is too many to hold in your head. The print version strips the site chrome and fits on two pages.

Not ready yet? 10K plans →

Hold yourself to it

Twelve-week blocks are not usually lost to injury or to the long runs. They are lost in week four, on a Tuesday, when the tempo run is scheduled and nobody would ever know.

RunMatch is one way to make that Tuesday visible. Stake your own money on completing the block and, if you miss it, the money goes to a recipient you named in advance rather than to us — RunMatch takes 0% of the pot. Or race a training partner for a pot and let the winner take it.

It needs an iPhone and an Apple Watch; runs without Apple Watch heart-rate data are rejected. The plan above is free and yours either way.

$21.14average win, one-day competition
$10median win
$740largest pot to date
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Half marathon questions, answered

Can I train for a half marathon in 12 weeks?
If you can currently run 3 miles without stopping, yes, and 12 weeks is the standard block for exactly that starting point. If you can't run 3 miles yet, you want a 16- to 20-week build instead — start with the 10K beginner plan, then come back to this one.
How many miles a week is half marathon training?
This plan runs 14 to 25 miles a week across four runs, peaking at 25 in week 11. That's a modest volume by half-marathon standards and it's chosen on purpose: it finishes people, which is what a first or second half needs. Higher-mileage plans exist and are for people chasing a time.
Why is the longest run only 12 miles and not 13.1?
Because the last 1.1 miles cost you more in recovery than they buy you in fitness, and race-day adrenaline reliably covers them. Almost every mainstream half plan stops between 10 and 12 for the same reason. You will be fine.
How slow should my long runs be?
Sixty to ninety seconds per mile slower than your goal race pace — there's a table on this page. 'Conversational' is the usual advice and it's too vague to act on, which is why the numbers are written out.
What if I miss a week of training?
There's a protocol further up this page. Short version: miss one week, repeat it. Miss two, drop back two weeks and accept a slower race. Miss three or more, and the honest move is to change your race rather than compress the plan — compressed blocks are where injuries come from.
Do I need to run four days a week?
Four is what this plan assumes. Three can work if you keep the long run and the tempo and drop one easy run, though you'll arrive at race day with less durability. Five is not better at this volume; the extra day is better spent on strength work.
What should I eat during a half marathon?
Most people need something around the 60–75 minute mark — a gel, chews, or a sports drink. The rule that matters more than the choice: practise it on your long runs from week 8 onwards. Race day is not the time to find out how your stomach feels about a gel.
What's a good half marathon time for a first-timer?
Between 2:00 and 2:30 for most people finishing a first half off a plan like this. The more useful target for a first one is negative splits — running the second half faster than the first — because it means you paced it properly, and almost nobody does.

Every RunMatch training plan

Same format on all of them: every session written out, free, printable, no email.

Twelve weeks. Forty-eight runs. 13.1 miles.

Print the plan, put the long runs in your calendar, and decide now what happens if you miss one.

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