How Long Does It Take to Train for a Marathon? A Beginner’s Timeline
A marathon is 42.2 kilometres, or 26.2 miles. For most people who sign up for one, the race itself is not the hard part. The hard part is the four or five months of ordinary Tuesday evenings and early Sunday mornings that come before it.
I have never met anyone who regretted training for a marathon properly. I have met plenty who regretted rushing it. A friend of mine went from almost no running to a marathon in ten weeks, finished it on willpower, and then did not run again for a year because of his knee.
So the honest answer to how long it takes is: longer than you would like, and it depends on where you are starting. This guide gives realistic timelines for different starting points, explains what the training involves, lays out a twenty-week beginner plan, and covers how to arrive at the start line uninjured.
At a glance
- Most beginners need 16 to 20 weeks of specific marathon training
- That assumes you can already run for about 30 minutes without stopping
- If you are starting from no running at all, allow 6 to 12 months
- A beginner plan has 3 to 4 runs a week, including one long run that builds to about 30 to 32 km
- Increase your running gradually. Too much, too soon is the main cause of injury
- The last 2 to 3 weeks are a taper, where you run less to arrive fresh
- Your first goal is to finish comfortably, not to hit a time
The short answer
| Your starting point | Time to be ready for a marathon |
|---|---|
| No running at all | 9 to 12 months: build up to 30 minutes of running, then a 5K and 10K, then a marathon plan |
| Can run 5 km without stopping | 20 to 24 weeks |
| Run regularly, 15 to 25 km a week | 16 to 20 weeks |
| Have run a half marathon recently | 12 to 18 weeks |
| Experienced runner, 40 km or more a week | 12 to 16 weeks |
Twenty weeks is a good default for a first marathon. It gives room to build slowly, absorb a missed week for illness or a busy period, and still taper properly.
Why it takes that long
Your heart and lungs adapt to running quickly, within a few weeks. Your bones, tendons, ligaments and joints adapt much more slowly, over months. This mismatch is the central problem of marathon training. You will soon feel fit enough to run further than your legs are ready for.
| What has to adapt | How quickly | What it gives you |
|---|---|---|
| Heart and blood volume | Weeks | More oxygen delivered to the muscles |
| Muscle endurance and energy stores | Weeks to months | The ability to keep going and to use fat as fuel |
| Tendons and ligaments | Months | Resilience against overuse injury |
| Bone | Months | Tolerance of repeated impact |
| Running economy and pacing skill | Months | Covering the distance with less effort |
| Mental endurance | Built through long runs | Confidence that you can keep going |
Injury risk is highest for new runners. A review that pooled injury studies found novice runners had roughly 18 injuries per thousand hours of running, compared with about 8 for recreational runners. A long, gradual build is how you avoid becoming part of that statistic.
Are you ready to start a marathon plan?
Before week one of a marathon plan, you should be able to say yes to these.
- I can run for 30 minutes without stopping, at an easy pace
- I have been running three times a week for at least two months
- I can comfortably cover 8 to 10 km in one go, even with walk breaks
- I have no current injury
- I can commit to three or four sessions a week for five months
If not, spend the next two to four months building a base. Start with run-walk intervals, work up to 30 minutes of continuous running, then to 5 km and 10 km. Our cardio exercises for beginners and how to start exercising when out of shape guides are good starting points.
See your doctor before training for a marathon if you are over 40 and new to exercise, have a heart condition, high blood pressure, diabetes or chest pain on exertion, or have a family history of heart disease at a young age.
The four phases of marathon training
| Phase | Length in a 20-week plan | What happens | Peak weekly distance |
|---|---|---|---|
| Base | Weeks 1 to 6 | Easy running to build the habit and the foundation | 25 to 32 km |
| Build | Weeks 7 to 13 | The long run grows. One run a week has some steady effort | 35 to 46 km |
| Peak | Weeks 14 to 17 | The longest runs of the plan | 50 to 56 km |
| Taper | Weeks 18 to 20 | Running is cut back so you recover and arrive fresh | Falling from 42 km to about 12 km before the race |
The types of run
| Run | What it is | How it should feel | Purpose |
|---|---|---|---|
| Easy run | Short, relaxed running | You could hold a conversation | Most of your training. Builds endurance with little stress |
| Long run | The weekly long outing | Easy, slower than you think | The most important session. Prepares body and mind for the distance |
| Steady or tempo run | A portion at a comfortably hard pace | You can speak in short phrases | Raises the pace you can sustain |
| Recovery week | A lighter week every third or fourth week | Refreshing | Lets your body absorb the training |
| Rest day | No running | Restful | When adaptation happens |
| Cross-training | Cycling, swimming, walking, strength work | Easy to moderate | Fitness without impact |
About 80 percent of your running should be easy. The most common beginner mistake is running easy days too fast, which leaves you too tired to do the long run well.
A 20-week beginner marathon plan
Four days of running a week, with an optional cross-training day. Distances are in kilometres. One mile is about 1.6 km.
This plan assumes you can already run 5 km comfortably. It is a general template, not individual coaching. Adjust it to how you feel, and repeat a week if you need to.
| Week | Run 1, easy | Run 2, easy or steady | Run 3, easy | Long run | Weekly total |
|---|---|---|---|---|---|
| 1 | 4 | 5 | 4 | 8 | 21 |
| 2 | 5 | 5 | 4 | 10 | 24 |
| 3 | 5 | 6 | 5 | 11 | 27 |
| 4, recovery | 4 | 5 | 4 | 8 | 21 |
| 5 | 5 | 6 | 5 | 13 | 29 |
| 6 | 5 | 8 | 5 | 14 | 32 |
| 7 | 6 | 8 | 5 | 16 | 35 |
| 8, recovery | 5 | 6 | 5 | 11 | 27 |
| 9 | 6 | 8 | 6 | 18 | 38 |
| 10 | 6 | 10 | 6 | 19 | 41 |
| 11 | 6 | 10 | 6 | 22 | 44 |
| 12, recovery | 5 | 8 | 5 | 14 | 32 |
| 13 | 6 | 10 | 6 | 24 | 46 |
| 14 | 8 | 10 | 6 | 26 | 50 |
| 15 | 6 | 10 | 6 | 29 | 51 |
| 16, recovery | 6 | 8 | 5 | 19 | 38 |
| 17 | 8 | 10 | 6 | 32 | 56 |
| 18, taper | 6 | 10 | 5 | 21 | 42 |
| 19, taper | 5 | 8 | 5 | 13 | 31 |
| 20, race week | 5 | 4 | 3, very easy | 42.2, the marathon | About 54 |
How to use it:
- Spread the runs out. A typical week is Tuesday, Thursday, Saturday and Sunday, with the long run at the weekend
- In weeks 7 to 17, make the middle portion of Run 2 steady: for example, 2 km easy, 5 km at a comfortably hard pace, 2 km easy
- Walk breaks on long runs are fine. Many first-time marathoners use a run-walk pattern for the whole race
- If you miss a week, repeat the week before it. Do not jump ahead
- If you miss more than two weeks, drop back three weeks in the plan
What a typical training week looks like
Here is how week 10 of the plan might fit into an ordinary working week.
| Day | Session | Time needed |
|---|---|---|
| Monday | Rest, or a 20-minute strength session | 0 to 20 minutes |
| Tuesday | Easy run, 6 km | About 40 minutes |
| Wednesday | Cross-training or rest | 0 to 40 minutes |
| Thursday | Steady run, 10 km: 2 km easy, 6 km steady, 2 km easy | About 65 minutes |
| Friday | Rest | |
| Saturday | Easy run, 6 km, plus a short strength session | About 60 minutes |
| Sunday | Long run, 19 km | About 2 hours 15 minutes |
That is roughly five to six hours a week at this stage, rising to seven or eight in the peak weeks. The long run takes most of a weekend morning once you include getting ready, eating afterward and recovering. It helps to agree that time with the people you live with before you start.
How long should the longest run be?
Most beginner plans peak with a long run of about 30 to 32 km, three weeks before the race. You do not run the full distance in training. The last 10 km on race day are covered on the strength of your whole training block, the taper and the occasion.
Research on recreational half and full marathon runners has found that those who covered more distance each week and did longer long runs in training tended to finish faster. More training, built sensibly, does make race day easier.
How fast can you safely build up?
You will often hear the ten percent rule: do not increase your weekly distance by more than ten percent. It is a reasonable guide, though the evidence for that exact number is weak. In one trial, novice runners who followed a gradual ten percent programme were injured just as often as those on a faster, standard programme.
The practical lesson is that no single rule protects you. A combination of habits does.
- Increase gradually, by roughly 10 percent a week or 2 to 3 km on the long run
- Take a lighter week every third or fourth week
- Change one thing at a time. Do not add distance and speed in the same week
- Keep easy runs easy
- Listen to pain. Muscle soreness that fades is normal. Pain that is sharp, one-sided, gets worse as you run or makes you limp is not
- Sleep and eat enough. Under-recovery makes any plan too much
Strength training for runners
Two short strength sessions a week make your legs more resilient and your running more efficient. They do not need to be long.
| Exercise | Sets | Reps | Why |
|---|---|---|---|
| Squat or goblet squat | 3 | 8 to 10 | Quadriceps and glutes |
| Romanian deadlift or hip thrust | 3 | 8 to 10 | Hamstrings and glutes |
| Reverse lunge or step-up | 2 | 8 per leg | Single-leg strength and balance |
| Calf raise, single leg | 3 | 12 to 15 | Calves and Achilles tendon |
| Side plank | 2 | 30 seconds per side | Hips and trunk |
| Dead bug or plank | 2 | 8 per side, or 30 to 45 seconds | Core |
Do these on easy-run days or cross-training days, not the day before your long run. In the final three weeks, reduce them to one light session a week. Our beginner leg workout at home and calf workout at home guides show the exercises.
Eating, drinking and long-run fuelling
- Eat enough. Marathon training is not the time for a strict diet. Under-fuelling raises the risk of injury and illness
- Carbohydrates are your main fuel. Rice, pasta, bread, potatoes, oats and fruit should feature in most meals
- Protein supports recovery. Around 1.4 to 1.8 grams per kilogram of body weight a day suits most runners
- Fuel during long runs. On any run longer than about 75 to 90 minutes, take in carbohydrate as you go. A common target is 30 to 60 grams an hour, from gels, chews, sports drink or simple foods such as bananas or dried fruit
- Practise it. Use your long runs to find out what your stomach tolerates. Never try anything new on race day
- Drink to thirst, and include sodium on long or hot runs
Our guides on what to eat before a workout and what to eat after a workout cover the basics.
The taper
In the last two to three weeks you run less, so that fatigue fades while fitness remains.
| Weeks to go | Weekly distance | Long run |
|---|---|---|
| 3 | About 75 percent of your peak | About 21 km |
| 2 | About 55 percent | About 13 km |
| Race week | A few short, easy runs | The marathon |
Many runners feel restless, heavy-legged or convinced they are losing fitness during the taper. That is normal. Do not add extra running to reassure yourself. The work is done.
Race day basics
- Nothing new. Wear shoes and clothes you have used on long runs, and eat what you have practised
- Start slower than you want to. The first 10 km should feel almost too easy
- Take fuel and water from early on, before you feel you need them
- Break it into sections: to 10 km, to halfway, to 30 km, then one kilometre at a time
- Walk if you need to. Brisk walk breaks through water stations help many first-timers finish stronger
- Stop and get help for chest pain, severe breathlessness, confusion or collapse
How long does a marathon take to run?
| Runner | Typical finish time | Average pace |
|---|---|---|
| Fast club runner | Under 3 hours | Under 4:16 per km |
| Experienced recreational runner | 3:30 to 4:00 | 5:00 to 5:40 per km |
| Average finisher | About 4:20 to 4:50 | About 6:10 to 6:50 per km |
| First-timer aiming to finish | 4:30 to 5:30 | 6:25 to 7:50 per km |
| Run-walk finisher | 5:30 to 6:30 | 7:50 to 9:15 per km |
For a first marathon, finishing healthy is the goal. Our pace calculator converts a target time into a pace per kilometre or mile.
Can you train for a marathon in 12 weeks, or 8?
| Timeframe | Realistic for | Risk |
|---|---|---|
| 8 weeks | Runners already doing 40 km or more a week with recent long runs of 20 km | Very high for anyone else |
| 12 weeks | Regular runners who have recently run a half marathon | Moderate. Little margin for missed weeks |
| 16 weeks | Runners with a solid 10 km base | Low to moderate |
| 20 weeks | Most first-timers who can run 5 km | Low |
| 6 to 12 months | People starting from no running | Lowest |
You may be able to finish a marathon on a short build. The question is what it costs. Compressed plans raise the chance of injury, of walking most of the second half, and of deciding you never want to run again.
If your race is too close, the sensible options are to switch to the half marathon if the event offers one, defer your place, or use a run-walk strategy and treat the day as a long, slow adventure.
Should you run a half marathon first?
It is not essential, but it is a good idea. A half marathon is 21.1 km, takes 10 to 12 weeks to prepare for from a 5 km base, and teaches you most of what you need: long runs, fuelling, pacing and what a race feels like. Many twenty-week marathon plans include one around week 10 or 12 as a practice run.
Common mistakes
- Starting a marathon plan with no running base
- Increasing too quickly
- Running every run at the same medium-hard pace
- Skipping recovery weeks
- Ignoring a niggle until it becomes an injury
- Making up missed runs by cramming them into the next week
- Neglecting strength work
- Not practising fuelling on long runs
- New shoes or kit on race day
- Going out too fast in the first 10 km
- Under-eating through training
The bottom line
For most beginners, training for a marathon takes 16 to 20 weeks, on top of a base that lets you run 30 minutes comfortably. Starting from no running at all, allow the best part of a year.
It takes that long because your joints, tendons and bones adapt far more slowly than your heart and lungs. Build gradually, keep most of your running easy, take a lighter week every month, and add a little strength training. Let the long run grow to about 30 km, then taper for two to three weeks.
Give yourself more time than you think you need. The extra weeks are what make the race enjoyable.
Running alone leaves gaps in upper body and core strength, which we explain in is running a full body workout.
Before any marathon plan, you need to be able to run comfortably for 30 minutes or more. My guide on how to increase running endurance shows how to get there safely.
A half marathon is a great stepping stone. My 12 week half marathon training plan includes a couch to half marathon option for complete beginners.
Many first-time marathoners use planned walk breaks. My guide to the run walk method explains ratios for every distance.
Frequently asked questions
How long does it take to train for a marathon?
Most beginners need 16 to 20 weeks of dedicated training, provided they can already run for about 30 minutes. If you are starting from no running at all, allow 9 to 12 months to build a base first and then follow a marathon plan.
Can I train for a marathon in 12 weeks?
Only if you already run regularly and have recently completed a half marathon or long runs of around 16 to 20 km. For a true beginner, twelve weeks is too short and greatly raises the risk of injury.
How many days a week should I run when training for a marathon?
Three to four days a week is enough for a first marathon. A typical week has two or three easy runs and one long run, plus one or two days of cross-training or strength work and at least one full rest day.
How long should my longest run be before a marathon?
About 30 to 32 km, or 18 to 20 miles, done roughly three weeks before race day. You do not need to run the full 42.2 km in training. The taper and your overall training carry you through the final stretch.
Can a beginner run a marathon?
Yes, with enough time. A healthy beginner who builds up gradually over six to twelve months can complete one, often using a run-walk approach. Get a medical check first if you are over 40 and inactive, or have any heart or health concerns.
How many miles a week do you need to run to train for a marathon?
A beginner plan typically starts at about 20 to 25 km a week, or 12 to 15 miles, and peaks at 50 to 55 km, or 30 to 35 miles. More experienced runners often train at higher volumes.
Do I need to run a half marathon before a full marathon?
It is not required, but it is strongly recommended. A half marathon gives you race experience and teaches pacing and fuelling at lower risk. Many marathon plans include one about halfway through as a practice event.
What happens if I miss a week of marathon training?
One missed week is not a problem. Repeat the previous week and continue. If you miss two or more weeks, drop back about three weeks in the plan and rebuild. Do not try to make up the lost distance all at once.
What’s next?
Reading is the easy part. Pick one of these and do it today.
