How long does it take to train for a marathon?

How long to train for a marathon depends on one thing more than anything else: where you're starting. If you already run a few times a week, a dedicated marathon build takes 16 to 20 weeks. If you can comfortably run a half marathon, you're at the short end of that. If you don't run at all yet, plan on something closer to a year, because the marathon build only starts once you're already a runner.

That's the honest version. Not the "marathon in 8 weeks" version. Below, the timeline for each starting point, and how to fit it around the gym if you lift, either by hand or with a Runna alternative that includes lifting.

How long does it take to train for a marathon? The short answer

Those ranges are coaching practice, not physics. They assume you're healthy, consistent, and fitting training around a normal life. For a sense of what the standard build looks like, Hal Higdon's Novice 1 marathon plan is 18 weeks with four runs a week, building to a 20-mile long run. That's the "16 to 20 weeks" in the table: a typical marathon training schedule for someone who's already running.

If you want a ready-made version of that build with strength sessions included, that's a marathon training schedule worth starting from. For everything that goes inside those weeks, from the long run to the taper, see a guide to how to train to run a marathon. This post just answers the "how long".

Why the build takes 16 to 20 weeks

People are often surprised that a plan for a single race takes four months. The time isn't arbitrary. Three things need it:

• ›The long run needs to grow slowly. Most plans add roughly a mile a week, with lighter weeks every third or fourth week, until a peak of around 18 to 20 miles. Start that from 8 miles and you need most of a 16-week block just for the long run.
• ›Your legs need time, not just your lungs. Coaches build mileage gradually on the working assumption that tendons, bones and joints take longer to get used to the pounding than your heart and lungs take to get fitter. Rushing the mileage is how runners end up sidelined. If anything hurts in a way that isn't normal training soreness, see a professional.
• ›The taper takes time too. The last two to three weeks are spent cutting volume so you arrive fresh. That's time you can't use for building.

Inside those weeks, most of your running is easy, with some marathon-pace and tempo work layered in as the build goes on. Knowing what pace to train at is what makes 18 weeks productive instead of 18 weeks of medium-hard slogging.

Long runs also teach you to eat and drink on the move, which is a skill, not an afterthought. More on what to eat before a long run if you're new to runs that last two hours or more.

If you lift: add strength, not weeks

You don't need a longer timeline because you lift. You need a smarter week.

During a marathon build, running is the priority and lifting supports it. Keep one or two strength sessions a week:

• ›Two sessions in the base phase and early build: one lower body, one upper or full body.
• ›One or two in the peak weeks, when the long runs get big.
• ›Heavy-ish, low volume. A few hard sets, not a bodybuilding split. No PR attempts until after the race.
• ›Lower body on an easy run day, never the day before the long run.

The lifting is worth keeping. A systematic review by Blagrove and colleagues (2018) found strength training improved running economy by 2–8% in the studies that measured it, with body composition not negatively affected. There's more on how much strength work runners need and what to put in those sessions.

What lifting does change is your scheduling. If you're in the middle of a strength block when you sign up, give yourself a few extra weeks to transition from lifting-first to running-first rather than flipping it overnight.

Timeline by starting point

Starting from zero: about 9 to 12 months

If you don't run at all, the marathon is a three-stage project:

1. ›Learn to run continuously. The NHS Couch to 5K program takes 9 weeks, three runs a week, building from short run-walk intervals to 30 minutes of continuous running. Many people take longer. That's fine.
2. ›Build a base. A few months of consistent easy running, gradually adding a fourth run and a longer weekend run. A half marathon somewhere in this stage is a great checkpoint.
3. ›The marathon build. 16 to 20 weeks once you're running regularly.

Add it up and you're looking at roughly 9 to 12 months. It's a long time. It's also the version where you enjoy race day.

Can run a few miles: about 6 to 8 months

If you can run 3 miles three or four times a week, skip stage one. Spend two to four months building to four runs a week and a long run of 8 to 10 miles, then start the 16 to 20 week build.

A half marathon training block is a smart way to spend those base months. It gives the base a structure and a deadline, and the race result tells you what marathon pace is realistic.

Already running 15 to 25 miles a week: 16 to 20 weeks

This is who most marathon plans are written for. You can go straight into a standard build. Choose the longer end if your current long run is under 8 miles, if you lift heavily and want to keep it, or if your life has a lot of travel in it.

Recent marathoner: 12 to 16 weeks

If you finished a marathon in the last year and kept running afterwards, you're starting from a higher floor. Twelve to sixteen weeks is usually enough to build back to peak long runs and sharpen. Less than that and you're mostly relying on fitness you already had.

The weeks after count too

Training time isn't the only time a marathon takes. The race itself takes a toll, and recovery takes longer than most first-timers expect. So, how long does it take to recover from a marathon? Plan on at least a couple of easy weeks before hard running or heavy lifting, and longer before another big build.

If you're scheduling a year around a marathon, block out recovery time on the calendar now. It's part of the project.

Can you train for a marathon in less time?

Yes, if you're already fit. No, if you're not.

An experienced runner can be marathon-ready in about 12 weeks. A beginner with 10 weeks to go is choosing between a painful finish and a smarter decision. Attempting a marathon with no training is possible in the sense that some people finish, but you're stacking the odds against yourself.

If your race is too soon:

• ›Drop to the half. Many marathons have a half on the same day.
• ›Defer. Many races allow deferral to next year, though policies vary, so check yours.
• ›Run-walk it. If you're committed, a planned run-walk strategy is far better than an unplanned walk from mile 16.

What to expect during the build

Sixteen to twenty weeks is long enough for some surprises:

• ›Week 4 to 6: It feels great. The plan feels easy. Don't add extra.
• ›Week 10 to 14: Peak volume. You're hungry, a bit tired, and your easy runs feel slower. Normal.
• ›The scale might move up. Marathon training weight gain is common, and it's usually not the disaster it looks like on the scale. If weight or eating is a real concern, talk to a registered dietitian.
• ›Life will interrupt. A cold, a work trip, a week where nothing goes right. A 16 to 20 week plan has room to absorb a missed week. An 8-week plan doesn't. That's another reason the longer timeline exists.

How exrsz handles this

exrsz builds your marathon plan backward from your race date, using your current level, the days you can train and your equipment, with running and lifting in one plan. If your timeline is short, the plan says so. It adapts each week to how your training went and reshuffles missed sessions so the build still lands on race day.

FAQ

How long should you train for a marathon?

Most runners who already run regularly should train for 16 to 20 weeks. If you're starting from no running, allow roughly 9 to 12 months so you can build a base first.

How long do you need to train for a marathon if you can already run a half?

Usually 16 weeks is enough, and 12 to 16 weeks if you've run a marathon within the last year and kept training.

Can I train for a marathon in 12 weeks?

If you're already running 20 or more miles a week and have raced a half recently, yes. If you're starting from little running, 12 weeks is too short for a comfortable finish.

How long does it take to train for a marathon from scratch?

About 9 to 12 months: a couple of months learning to run continuously, a few months of base building, then a 16 to 20 week marathon build.

Do I need to stop lifting to train for a marathon?

No. Keep one or two strength sessions a week, reduce the volume, and schedule heavy lower-body work away from your long run.