20-week marathon training plan for beginners

Beginner here means a first marathon, not a first run. Week 1 is 18 miles over three runs, with a 9.9-mile long run on Sunday, so the plan assumes you already run about 15–18 miles a week and can cover 8.1–9.9 miles at an easy pace without stopping. Most people who fit that description have finished a half marathon or are close to it.

If your longest recent run is under 6.2 miles, do not start here. The 16-week beginner half marathon plan starts at a 6.2-mile long run and builds to 12 miles, which covers the base this plan opens with.

Choose it if you have the time, or if you are coming off a low base or an injury. Smaller steps and 3 cutback weeks make it the most forgiving version; the cost is a longer stretch of discipline, not a harder one. The other lengths are the 12-week beginner marathon plan and 16-week beginner marathon plan.

20 weeks split into four building blocks separated by cutback weeks, two peak weeks, three taper weeks and race week. Every number below is the plan in the table above.

Weeks 1-3, base. Long runs of 9.9, 11 and 11 miles, in weeks of 18, 19 and 20 miles. This is where the routine gets built: every run is easy except one steady effort, and none of it should feel like a test. Easy means you could still speak in full sentences; how to breathe while running explains the talk test.

Week 4, cutback. The long run drops to 8.1 miles from 11 miles and the week to 15 miles. Run it as written. The easier week is where the previous three turn into fitness, and it is the week beginners most often skip.

Weeks 5-6, base. Long runs of 12 and 13 miles, in weeks of 22 and 23 miles. The climb resumes from where the last full week left off, not from the cutback.

Week 7, build. A 14-mile long run in a 25 miles week. The long run carries the progression; the weekday runs grow in proportion to it.

Week 8, cutback. The long run drops to 9.3 miles from 14 miles and the week to 17 miles. Same job as the first cutback: absorb the block before the next one.

Weeks 9-11, build. Long runs of 14, 15 and 16 miles, in weeks of 25, 27 and 28 miles.

Week 12, cutback. The long run drops to 11 miles from 16 miles and the week to 20 miles.

Weeks 13-14, build. Long runs of 16 and 17 miles, in weeks of 29 and 32 miles.

Weeks 15-16, peak. The hardest stretch of the plan: two weeks at 32 miles, each with a 18-mile long run. If a fortnight in your calendar cannot absorb that, this is the one to protect.

Weeks 17-19, taper. Volume comes down to 22, 13 and 9.3 miles and the long run to 12, 7.5 and 5 miles. You keep the frequency and lose the fatigue; fitness does not fade in two or three weeks, tiredness does.

Week 20, race week. Tue 3.1 miles easy and Thu 1.9 miles shakeout, then the race on Sunday. That is all the running in the six days before the start line.

Every length starts from the same 18 miles week 1 and reaches the same 32 miles peak week and 18-mile long run. The length decides how gradually you get there, not where you end up: the 12-week plan reaches its longest run in week 7, the 20-week plan in week 15, with 3 cutback weeks instead of 1.

This plan's 459 miles is about 18 times the race distance, roughly 83 hours of easy running at 6:30 to 7:00 per kilometre. How long is a marathon breaks down what that time costs week by week.

Cutback weeks. Weeks 4, 8 and 12 drop the long run to 8.1, 9.3 and 11 miles, about 70% of the last full week's. Adaptation happens in the easier week, not the hard one.

Steps are capped at 20%. No long run is more than a fifth longer than the last full week's. The biggest single step in this plan is +1.2 miles, from week 5 to week 6. Where a shorter plan cannot reach the usual peak inside that limit, it settles for a lower peak instead of taking an unsafe step.

A real taper. The three weeks before race week come down to 22, 13 and 9.3 miles, and race week carries 5 miles of running before the start line.

Pace comes from your goal. The table gives distances, not paces: if you are aiming for a time, 5-hour marathon pace is 11:27 per mile and 4-hour marathon pace is 9:09.