How many weeks do you need?
Run 42 builds marathon plans from 12 to 24 weeks, counted back from race day. Which length suits you depends on where you start:
- 12 to 15 weeks if you already run regularly and have raced a half marathon or more in recent months. There’s no time for a base phase, so the plan goes straight to quality work.
- 16 to 19 weeks for most runners. This is the classic marathon block: a short base, then build, peak and taper.
- 20 to 24 weeks for a first marathon, or after three months or more off. If you are coming back from a long break, the plan opens with eight weeks of base before any hard running.
Every race page on this site shows the start date of a 12, 16, 20 and 24-week plan for its next edition, for example the Paris Marathon or the New York City Marathon.
The five phases
Base
Easy running only. The goal is to get used to running more often and for longer, without the strain of speed work. The long run grows from about one hour to an hour and a half.
Build
One quality session a week joins the easy runs, taking turns between threshold intervals (such as 3×8 minutes) and VMA repeats (such as 6×400 m). These raise the pace you can hold comfortably. The long run keeps growing.
Peak
The longest phase and the most specific. Each week has a run at marathon pace, growing from 8 to 10 to 12 km, plus a threshold or VMA session. From a third of the way in, the long run finishes with 2×5 km at marathon pace. The longest long run, three hours at most, lands about three weeks before race day.
Taper
Two weeks where the volume drops to about 60%, then 40%, of the peak week. The rhythm stays the same, with a short marathon-pace rehearsal, so you arrive fresh but not flat. More in the marathon taper.
Race week
Three short easy runs, the last one a 15-minute shake-out with a few strides, and the race.
Weekly volume
The first week starts from what you have run lately: someone just off a half marathon starts higher than someone whose last race was a 5K, and time off brings the start down. From there the volume grows about 10% a week in base and build and about 5% a week in the peak phase, up to a ceiling set by how often you run. In Run 42 that ceiling is around 55, 60 or 65 km a week for three, four or five runs.
Every fourth week is a cutback week, about 25% lighter, long run included. That is when the training of the previous three weeks turns into fitness.
The long run
Long runs are set in minutes rather than kilometres, at easy pace. A three-hour run covers 35 km for a fast runner and 22 km for a slower one, and that’s the point: the strain on the body depends on time on your feet. The long run guide goes into detail.
Paces
All the paces in a plan come from your goal time, using equivalent race performances rather than fixed offsets:
- Marathon pace: your goal time divided by 42.195 km.
- Easy: 15 to 27% slower than your marathon pace.
- Threshold: the pace you could race for about an hour.
- VMA: about your 3 km race pace.
The marathon pace chart lists them for every goal from 2h30 to 6h00, and training pace zones explains what each one is for.
Sample plans by goal time
Each of these is a full 16-week plan built by the app, week by week, with every session:
- Sub-3 marathon plan (five runs a week)
- Sub-3:30 marathon plan (five runs a week)
- Sub-4 marathon plan (four runs a week)
- Sub-4:30 marathon plan (four runs a week)
- Sub-5 marathon plan (three runs a week)
- First marathon plan (20 weeks, three runs a week)
In the app, you pick your race, your goal time, how many days a week you can run and your long-run day. Run 42 builds the plan to your race date, shows today’s session on the home screen and, if you connect Strava, puts what you ran next to what was planned.
