Training for your first marathon: an 18-week plan

A concrete 18-week plan for your first marathon: weekly mileage by phase, long runs, tempo work, strength, race-day fuelling and the taper.

A first marathon is decided less by willpower than by how much mileage your body absorbs without breaking. If you currently run 25 to 30 km a week and 10 km feels routine, 18 weeks is enough to get you to the finish on your own legs. What follows is a plan that works for most people who can run 4 to 5 days a week.

What you need before week one

The entry requirement is roughly three months of consistent running with no breaks longer than 10 days. Concretely: 25–30 km per week across 3 to 4 runs, plus one run of 10 to 12 km you finish without walking. If you do not have that, spend 8 to 12 weeks building a base first. Skipping this step is the single most common reason people get injured in weeks 6 to 10.

You also want two pairs of shoes you rotate and replace around 600–800 km, and a watch or phone that tracks pace. Nothing else.

What a typical week looks like

Five running days, two days off or easy walking and cycling. The split:

Three easy runs of 6 to 12 km, at a pace where you can speak in full sentences. That is usually 60 to 90 seconds per kilometre slower than your goal marathon pace.
One quality session (tempo or intervals).
One long run on the weekend.

Aim for roughly 80 percent easy and 20 percent hard. If every session feels moderately hard, that is the worst possible setup: not enough stimulus to improve, too much fatigue to recover.

The plan, phase by phase

Weeks 1–4: base

Start at 32 km per week and add about 10 percent weekly: 32, 35, 39, then cut back to 30 km. Long runs go 14, 16, 18, then back to 14 km. The quality session stays simple: 20 minutes easy, then 4 x 5 minutes at a pace where you can still manage a short sentence, with 2 minutes of easy jogging between.

Weeks 5–10: build

Mileage climbs from 42 to 58 km. Every fourth week drops about 25 percent. Long runs go 20, 22, 26, 18 (down week), 28, 24 km. Quality: 5 x 1000 m at the pace you could hold for a 5 km race, with 2–3 minutes recovery, or 3 x 10 minutes at threshold with 2 minutes jog.

Weeks 11–15: specific

Peak at 60 to 68 km per week. Do two long runs of 30 to 32 km, at least 14 days apart, and never run longer than 3 hours 15 minutes regardless of distance. Add marathon-pace work: 24 km with the last 12 km at goal race pace. That session tells you your realistic target more accurately than any calculator.

Weeks 16–18: taper

Drop volume to 45, 34, then 22 km, but keep the intensity: short reps such as 6 x 400 m at marathon pace or slightly faster. Your last long run is 16 km, three weeks out. The final three days are 20 to 30 minutes easy, nothing more.

Strength, twice a week

30 to 40 minutes, the day after a hard run rather than the day before. Six exercises cover it:

Squat 3 x 6–8
Romanian deadlift 3 x 8
Walking lunge 3 x 10 per leg
Single-leg calf raise 3 x 15
Glute bridge 3 x 12
Plank 3 x 45 seconds

The goal is not muscle mass. It is calf, hip and trunk endurance in the last 10 km of the race, which is exactly where form falls apart.

Fuel and fluid

Efforts over 90 minutes need 30 to 60 g of carbohydrate per hour, and a trained gut tolerates up to 90 g when different sugar types are mixed. In practice that means taking something every 25 to 30 minutes from about the 45-minute mark. Fluid: 400 to 800 ml per hour, more in heat, with some sodium.

Everything you plan to eat and drink on race day has to be tested on at least three long runs. Race morning is not the place to experiment.

For the two days before the race, raise carbohydrate intake to 7–10 g per kilogram of body weight per day and cut back on fibre. Breakfast 3 hours before the start: 1 to 2 g of carbohydrate per kilogram, familiar food, nothing fatty and nothing new.

Race day

Run the first 5 km 10 to 15 seconds per kilometre slower than goal pace. Almost everyone who blows up in a first marathon does the damage in the first 30 minutes and pays for it after 30 km. If your pace does fall apart, switch to plan B: 3 minutes running, 1 minute walking, repeat to the finish. For a first marathon the target is finishing uninjured; the time comes second.

When to see a doctor

Get checked before you start the plan at all if you are over 40 and have been inactive, or if you have high blood pressure, diabetes, asthma or known heart disease. See a doctor promptly, rather than adjusting training on your own, if you get:

chest pain, pressure or tightness during exertion
fainting, dizziness or a sense of skipped or racing heartbeats
a pinpoint pain on a bone (shin, foot, hip) that hurts while walking or at night, which can be a stress fracture
pain lasting more than two weeks or changing the way you walk
a swollen joint, or a family history of sudden cardiac death before age 50

The short version

Enter the plan with a 25–30 km weekly base; 18 weeks is a realistic window.
Five runs a week, 80 percent easy, peak at 60–68 km, long run capped at 32 km or 3 hours 15 minutes.
Strength twice a week, six exercises, 30–40 minutes.
Practise 30–60 g of carbohydrate and 400–800 ml of fluid per hour on long runs, never for the first time on race day.
Taper for three weeks, and deliberately run the first 5 km slower than goal pace.