TL;DR. A first marathon is 26.2 miles (42.2 km). This free 16-week plan is built for UK runners who can already run 5 to 6 miles continuously and want to finish their first marathon strong and injury-free. You run three or four times a week (one easy, one quality, one long) and add one or two strength sessions. The long run climbs from 6 miles in week 1 to 20 miles in week 13, then a three-week taper carries you to race day. Peak weekly mileage sits between 30 and 40 miles. If you want this plan hand-built around your real pace and weekly schedule, the Edge coaching team will write you one within 24 hours of signing up.

Who this 16-week marathon plan is for

This plan is written for UK runners getting ready for their first marathon. It assumes a real starting point. You should be able to run 5 to 6 miles in one go without stopping, and you should have done some kind of structured running for at least three months. Most people who use this plan have finished a half marathon, a long parkrun streak, or a 10-mile race in the last year.

You do not need to be fast. Pace does not matter for finishing your first marathon. What matters is that you can already cover the distance on a long Sunday run without your knees, hips, or calves shutting you down. If you can run 10 km without stopping but you have never gone further, start with our 12-week half marathon plan first and come back to this one next year.

You also need 16 free weeks. Not 12. Not 14. A first marathon training block needs time for the long run to grow safely, time for your body to absorb the work, and time to taper. Cutting the plan short is the single biggest mistake new marathoners make.

How the plan is built

Every week of the plan has the same shape. One easy run, one quality session, one long run, and one or two strength sessions. That structure repeats for 16 weeks, but the volume and the difficulty change. Here is what each session does for you.

Easy runs

Easy runs make up the bulk of your weekly mileage. They are slow. Slower than you think. The point is to spend time on your feet, build your aerobic engine, and let your tendons, bones, and joints get used to the load. A good test is the talk test. You should be able to hold a full conversation while running. If you cannot, you are going too fast.

Quality sessions

Once a week you do one harder session. In the early weeks this is a tempo run, which means 20 to 30 minutes at a comfortably hard pace, the kind you could hold for a 10K race. In the middle weeks it becomes longer tempo work or marathon-pace miles inside an easy run. In the late weeks it shifts to race-pace blocks inside your long run. Only one quality session a week. Two is too many for a first-time marathoner.

The long run

This is the most important run of the week. It is also the slowest. Long runs build the endurance, fuel storage, and mental toughness you need for 26.2 miles. They start at 6 miles in week 1, build by roughly a mile a week, and peak at 20 miles in week 13. After that the long runs come down through the taper.

Strength and mobility

One or two short strength sessions a week make a real difference to injury risk and late-race form. You do not need a gym. Bodyweight squats, lunges, hip bridges, single-leg work, and core hold the line. Two short sessions of 20 to 30 minutes is plenty. Edge includes coach video demos for general strength and mobility moves in every membership.

The full 16-week plan

Below is the complete week-by-week schedule. Distances are in miles. Strength sessions are marked S. Rest days are marked Rest. Cross-train means low-impact aerobic work like cycling, swimming, or the rowing machine.

Notice the cutback weeks at week 4, week 8, and week 12. These are not optional. Every fourth week your mileage drops by about 30 percent. Your body absorbs the work and rebuilds stronger. Skipping cutbacks is how runners end up with shin splints in week 10.

Pace targets and how to find them

You do not need a watch that costs three hundred pounds to train for a marathon. You do need to know roughly how fast each kind of run should be. The easy way is to start from your current 5K race pace and work outwards.

These are rough guides. Heat, hills, sleep, and life all move the numbers around. The key idea is the gap. Easy runs should feel a long way slower than tempo runs. If your easy pace and your tempo pace are the same number, you are training too hard on easy days and too easy on hard days, which is the most common pattern for new marathoners.

How to run the long run

The long run is the cornerstone of marathon training, and most first-timers run it badly. Here are the rules that turn the long run from a slog into the most useful session of your week.

Start slow. The first mile of a long run should feel almost embarrassingly easy. If you are panting in the first mile, you started too fast and you will pay for it later. Aim to finish faster than you started.

Use the route. Pick a flattish loop you can repeat, or a point-to-point route that ends near coffee and a sit down. Boring is fine. Predictable is better than scenic when you are 16 miles deep and bonking.

Fuel before, during, and after. Eat a real breakfast 60 to 90 minutes before. From 90 minutes of running onwards, take a gel or some chews every 30 to 40 minutes. Sip water or a sports drink. Practise on training runs what you plan to do on race day. Edge does not give you nutrition guidance, so use a sports nutrition guide or talk to a running dietitian for the detail.

Carry the basics. Phone, ID, a £10 note, and enough fuel for the planned distance plus 20 minutes. A small running vest pays for itself the first time you bonk in a country lane.

Walk if you need to. Walking is not failure. Walking 30 seconds at every mile marker on a 20-mile run keeps your form clean and your heart rate sensible. Many first-time marathoners run their best race using a run-walk strategy.

Strength sessions for first-time marathoners

Two short strength sessions a week is the sweet spot. Any less and you leave free injury protection on the table. Any more and your legs are too tired for the next quality run.

A simple weekly session looks like this. Bodyweight squats 3 sets of 12. Walking lunges 3 sets of 10 each leg. Single-leg hip bridges 3 sets of 10 each side. Calf raises 3 sets of 15. Plank 3 sets of 30 to 45 seconds. Side plank 3 sets of 20 to 30 seconds each side. Bird-dog 3 sets of 8 each side. Total time about 25 minutes.

If you have access to a gym, add goblet squats, Romanian deadlifts, and step-ups with light dumbbells. The Edge app includes coach video demos for general strength and mobility moves so you can see exactly how each one should look.

The taper, weeks 14 to 16

The taper is the three weeks before race day where your body absorbs all the training you have just done. Mileage drops. Intensity stays. The goal is fresh legs, not lost fitness. You will feel weird. Most runners get phantom pains, restless legs, mood dips, and the certain conviction that they have lost their fitness. None of this is true. The taper is working.

Week 14 is your first taper week. Mileage drops to around 75 percent of peak. You still do a quality session and a long run, but everything is a notch smaller. Week 15 cuts again to roughly 55 percent of peak. The Sunday run is 10 miles, not 18. Week 16 is race week. Two short easy runs with a few strides, plenty of sleep, and then the marathon.

Race week and race day

Race week is mostly about doing less. Sleep more. Eat a bit more carbohydrate from Wednesday onwards. Drink water steadily through the week. Avoid new foods and new shoes. Lay out your kit two days before. Pin your number on the night before.

On race morning, eat the same breakfast you have eaten before every long run. Get to the start with time to spare. Use the toilet twice. Start slower than you want to. The single biggest first-marathon mistake is going out too fast in the first three miles because everyone around you is doing the same.

From mile 18 onwards, the race becomes a mental game. Break it down. Just get to the next aid station. Just get to mile 20. Just hold this pace for one more song. Smile at the crowds. Walk through aid stations if you need to. Cross the line, eat everything in sight, and ring the people you love.

Interactive: plan start date calculator

Tell the calculator your race date and a few details about your running, and it will tell you when to start the plan, what your peak weekly mileage will be, and a sensible finish-time range to aim for.

Common first-marathon mistakes

Going out too fast on race day. Adrenaline plus crowd noise plus 26 miles of fresh legs makes everyone feel like a hero in mile one. The pace you can hold for the first 5K is not the pace you can hold for the marathon. Start 15 to 20 seconds per mile slower than goal pace and let the second half be the strong half.

Skipping cutback weeks. The plan has cutback weeks for a reason. They are not rest weeks. They are absorption weeks. Skip them and your week 11 long run is the run that breaks you.

Doing the easy runs too hard. If your easy runs leave you tired the next day, they are not easy. Slow down. The whole plan only works if 80 percent of your running is genuinely easy.

Trying new fuel on race day. Whatever gel, drink, or chew you plan to use, practise it on every long run from week 6 onwards. Race day is the worst possible day to discover that one brand of gel turns your stomach.

New shoes on race day. Race in the shoes you trained in, or in a pair of the same model with at least three long runs on them. The exciting carbon-plated pair you saw on Instagram is not the pair to debut at mile zero.

Ignoring the niggles. A small ache that sticks around for three runs is a problem. Get a physio appointment in week 2, not week 13. Most first-marathon DNFs happen because someone tried to train through a niggle for six weeks instead of taking three days off.

How Edge fits into your marathon training

Edge is a UK fitness coaching app with more than 17,000 members. We are not a marathon-only app. We help runners, lifters, and general fitness members train consistently, with real human coaches in the loop.

For marathon training specifically, the part of Edge that matters most is the starting plan. Within 24 hours of signing up, the coaching team will hand-build your starting plan around your real running pace, the days you can actually train, and the kit you have at home or in the gym. A generic 16-week template treats every runner the same. Your Edge plan does not. It is built by a person, for you, and adjusts as you progress.

From there, Edge gives you Flexi Swap to move sessions when life gets in the way, Edge AI for 30-second adjustments and quick questions, direct sync with Strava, Garmin, Apple Watch, and Coros, lean voice prompts during runs, and progress tracking that your coach can see and respond to. General strength and mobility sessions with coach video demos sit alongside your runs.

What Edge does not do is auto-prescribe race-day pacing or build you a nutrition plan for race week. For those, use the template above, work with a running dietitian if you want detail, and lean on your coach for the running side.

Free 7-day trial on the 6-month and annual plans. £19.99 a month, or £119.99 for the year.

Keep reading

• 12-week half marathon plan for UK beginners
• Marathon pace calculator, splits, and fuelling
• London Marathon complete training and race guide
• Hitting the wall: a beginner's guide

FAQs

Is 16 weeks long enough to train for a first marathon?

Yes, if you start the plan already able to run 5 to 6 miles continuously. The 16 weeks are for building the long run from 6 miles up to 20 miles, adding quality work, and tapering. If you cannot run 5 to 6 miles today, add a 6 to 12 week base-building block before week 1.

How many days a week do I need to run?

Three or four. Three works fine if you add one strength session and one cross-training session. Four is the sweet spot for most first-time marathoners. Five is only sensible if you have run for several years and your body handles the load well.

What pace should I aim for in my first marathon?

A safe rule is to add 60 to 75 seconds per mile to your current half marathon pace. Or use the pace table in this guide. Most first-time marathoners finish between 4:00 and 5:30. There is no shame in any of those numbers. Finishing strong matters more than the clock.

Do I have to run 20 miles before the marathon?

One 20-mile long run is the gold standard. Some plans go to 22. If you do two 18-mile runs instead of one 20, that is fine. What is not fine is showing up to race day with a longest run of 14 miles.

What if I miss a week of training?

One missed week, you pick up where you left off. Two missed weeks, you repeat the last week you completed and then move on. Three or more missed weeks, especially from illness or injury, talk to a coach or physio about whether to defer the race. With Edge, your coach will rework the plan for you.

Should I do a half marathon during this plan?

Many runners use weeks 9 to 11 to race a half marathon as a tune-up. It works well if the half slots into a planned long run weekend and you treat the next week as a cutback. It does not work well if you race the half all out and then try to do a 17-mile long run the following Sunday.