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Running · 12 weeks

12-week marathon training plan

A 12-week marathon training plan takes a club runner on 45 km a week with a 1:55 half marathon from where they are to race day in 13 weeks, building to 77 km in the biggest week. It spends 5 weeks in base, 3 weeks in build, 2 weeks in peak, 2 weeks in taper, with 2 lighter weeks to absorb the work, on 6 days a week. That is 4 weeks shorter than we would choose — see below for what that changes.

Build my marathon plan — free

Built from your own numbers and your own week. The first week is free.

Is 12 weeks enough?

12 weeks is not enough to add meaningful aerobic fitness for a marathon. What it can do is keep you healthy, sharpen what you already have and get the pacing right. If you are starting from a solid base of long runs, you can finish well; if you are not, the kindest thing this plan can tell you is to pick a later race or a shorter distance.

What the weeks are for

Base5 weeks — aerobic volume, mostly easy, the foundation everything else stands on
Build3 weeks — the harder sessions arrive and volume keeps climbing
Peak2 weeks — the biggest, most race-specific weeks
Taper2 weeks — volume drops, intensity stays, you arrive fresh
Lighter weeks2, roughly every fourth week
Total730 km, 95 hours

The 13 weeks

Generated for a club runner on 45 km a week with a 1:55 half marathon.

WeekPhaseVolumeLoad
1Base45 km258
2Base49 km282
3Base53 km303
4Base · down37 km220
5Base59 km331
6Build60 km364
7Build65 km390
8Build · down49 km287
9Peak70 km416
10Peak77 km450
11Taper66 km375
12Taper51 km292
13Race · race47 km407

The biggest week, session by session

Week 10, peak phase — the heaviest week of the block.

MondayEasy run — 1h02, 8.8 km
TuesdayThreshold — 2 × 10 min — 0h54, 8.1 km
TuesdayStrength — lower body — 0h27
WednesdayEasy run — 1h12, 10.4 km
FridayRace pace — 9 km — 1h12, 11.4 km
SaturdayEasy run — 1h12, 10.4 km
SundayLong run with a fast finish — 3h00, 28.1 km

The paces

Pace bandPer kilometre
Easy — the ceiling, not the target6:19
Marathon pace5:41
Threshold5:22
Interval (VO₂max)4:51

Computed from VDOT 38.3, derived from that time trial using Jack Daniels' model. Your own numbers will differ — the plan builds these from a time trial you enter.

What this plan says out loud

Worth knowing

Some sessions have been cut to fit the time you said you have — 75 minutes on a weekday and 180 at the weekend. That is a real constraint and the plan respects it, but be aware the long session is the one that matters most: if you can find more time anywhere, find it on the weekend.

Worth knowing

On 6 days a week there is nowhere to put 34 km without prescribing runs nobody should be doing. The plan caps individual easy runs at 14 km and carries less volume than your target as a result. More days would do more for you than longer runs.

Worth knowing

Race day looks like about 3:57:48 on today's fitness — Run 3h 58. Assumes a flat course, reasonable conditions and a sensible first half.

Common questions

Is 12 weeks enough for a marathon?

Only if you already train regularly. What it can do is keep you healthy, sharpen what you already have and get the pacing right.

How many days a week does it train?

6, on Monday, Tuesday, Wednesday, Friday, Saturday, Sunday in this example. You tell the plan which days you actually have, and it never puts two hard days back to back.

What is the longest session?

Long run with a fast finish, about 3h00 and 28 km. It is capped by share of the week, by absolute length, and by the time you say you have.

Can I use this if I train at altitude?

Yes, and you should say so when you build it. Paces and power are corrected for the difference between where you tested and where you train — in Johannesburg that is roughly 8%, or about 26 seconds a kilometre on an easy run for a 20-minute 5 km runner.

Other marathon plans

Goal times

South African races at this distance

Worth reading

Build my plan