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Running · 12 weeks12-week half marathon training plan
A 12-week half marathon training plan takes a club runner on 35 km a week with a 52-minute 10 km from where they are to race day in 13 weeks, building to 43 km in the biggest week. It spends 5 weeks in base, 4 weeks in build, 2 weeks in peak, 1 week in taper, with 2 lighter weeks to absorb the work, on 6 days a week.
Build my half marathon plan — freeBuilt from your own numbers and your own week. The first week is free.
12 weeks is a comfortable length for a half marathon. There is room for a proper base before the harder work, lighter weeks to absorb it, and a taper that leaves you fresh rather than flat.
What the weeks are for
| Base | 5 weeks — aerobic volume, mostly easy, the foundation everything else stands on |
|---|---|
| Build | 4 weeks — the harder sessions arrive and volume keeps climbing |
| Peak | 2 weeks — the biggest, most race-specific weeks |
| Taper | 1 week — volume drops, intensity stays, you arrive fresh |
| Lighter weeks | 2, roughly every fourth week |
| Total | 480 km, 69 hours |
The 13 weeks
Generated for a club runner on 35 km a week with a 52-minute 10 km.
| Week | Phase | Volume | Load | |
|---|---|---|---|---|
| 1 | Base | 35 km | 207 | |
| 2 | Base | 34 km | 201 | |
| 3 | Base | 35 km | 205 | |
| 4 | Base · down | 29 km | 169 | |
| 5 | Base | 36 km | 212 | |
| 6 | Build | 39 km | 235 | |
| 7 | Build | 40 km | 244 | |
| 8 | Build · down | 38 km | 224 | |
| 9 | Build | 39 km | 247 | |
| 10 | Peak | 43 km | 264 | |
| 11 | Peak | 43 km | 264 | |
| 12 | Taper | 42 km | 245 | |
| 13 | Race · race | 26 km | 215 |
The biggest week, session by session
Week 10, peak phase — the heaviest week of the block.
| Tuesday | Threshold — 2 × 10 min — 0h54, 8.1 km |
|---|---|
| Tuesday | Strength — lower body — 0h27 |
| Wednesday | Easy run — 0h35, 4.5 km |
| Friday | Race pace — 6 km — 0h55, 8.4 km |
| Saturday | Easy run — 0h35, 4.5 km |
| Sunday | Long run with a fast finish — 1h56, 17.7 km |
The paces
| Pace band | Per kilometre |
|---|---|
| Easy — the ceiling, not the target | 6:20 |
| Marathon pace | 5:42 |
| Threshold | 5:23 |
| Interval (VO₂max) | 4:52 |
Computed from VDOT 38.2, 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
Some sessions have been cut to fit the time you said you have — 60 minutes on a weekday and 120 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.
On 6 days a week there is nowhere to put 28 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.
Race day looks like about 1:55:18 on today's fitness — Run 1h 55. Assumes a flat course, reasonable conditions and a sensible first half.
Common questions
Is 12 weeks enough for a half marathon?
Yes, for most people who already exercise. We would choose at least 12 weeks, and this is 12.
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 2h00 and 19 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 half marathon plans
Goal times
- Sub-2:30 half marathon training plan
- Sub-2:15 half marathon training plan
- Sub-2 hour half marathon training plan
- Sub-1:45 half marathon training plan
- Sub-1:30 half marathon training plan