16-week marathon training plan for runners with a base

Sixteen weeks is a common length for a marathon block: long enough to build the long run to 20 miles with lighter weeks along the way, short enough to stay focused. This 16-week marathon training plan is for runners who already have a running habit and want to turn it into a marathon. It uses five runs a week, one structured workout, a marathon-pace habit and a three-week taper.

Who this plan is for

Start this plan if you can say yes to all of these:

• You have been running 15 to 20 miles a week for at least the last month or two.
• Your longest regular run is about 7 miles, at a comfortable pace.
• You can fit five runs a week, one of them long, into your schedule.

Week 1 asks for 20 miles with a 7-mile long run, so it should feel like a normal week, not a leap. If you are below that, the marathon training plan for beginners takes 18 weeks, uses four runs a week and starts lower.

You can run this plan for a finish or for a time. If your goal is a specific time, such as the time you need to qualify for Boston, use your goal pace for the marathon-pace segments. A clear target such as four hours has its own plan with exact paces: the sub-4-hour marathon plan.

Check with your doctor before you start if you have a heart or lung condition, diabetes, high blood pressure, a recent injury or any other health concern. Rush University's sports medicine guidance lists chest pain, unexplained fainting, a heart murmur, high blood pressure, a close relative with heart disease before 50, and coronary artery disease over age 35 as reasons to see a doctor before marathon training.

12, 16 or 20 weeks: which block fits

Cleveland Clinic notes that most marathon plans range from 12 to 20 weeks, and that the right length depends on your fitness and goals. The question is how much base you bring.

The 12-week version works because weeks 1 to 4 of this plan are there to build from 20 to 26 miles a week. If you are already doing that, you can skip them. A 2024 analysis of 92 published 12-week marathon plans found that their peak week came, on average, 3.6 to 4.4 weeks before the race, depending on volume, so a 12-week block is really eight or nine weeks of building and three or four of tapering. There is no room in it to build a base from scratch.

The 20-week version adds four easy base weeks in front of week 1. Run three or four easy runs a week with long runs of 5, 6 and 7 miles, then a lighter week with a 5-mile long run. Keep all of it conversational. Then start week 1.

The 16-week plan

Distances are in miles. Monday and Friday are rest days. Race day is the Sunday of week 16.

How to read the workout column: "6: 3 at marathon pace" means a 6-mile run with 3 miles in the middle at your goal marathon pace, and the rest easy. Every workout includes its warm-up and cool-down in the total.

The runs, explained

• Easy: conversational. Most of your miles. The 92-plan analysis found that published plans put about 77 to 82% of their distance in the two lowest of five intensity zones, most of it in zone 2, the steady aerobic zone of long runs (73 to 80% of maximum heart rate). Only about 4 to 8% was in the two hardest zones. This plan follows the same pattern: one workout a week, everything else easy or long.
• Strides: short, relaxed accelerations of about 20 seconds, walking or jogging back to recover. They keep your legs quick without adding fatigue.
• Steady: a notch faster than easy; you could still speak in short sentences.
• Tempo: comfortably hard. You could say a few words but wouldn't want to chat. Jog 2 to 3 minutes between repeats.
• Marathon pace: your goal pace for race day, no faster. Look it up in the marathon pace chart. These segments teach you what the pace feels like and give you a place to rehearse fueling at race speed.
• Long run: slow. A University of Utah Health physical therapist suggests running it one to two minutes per mile slower than your anticipated race pace, and warns that long runs run too fast leave you without enough recovery.

How the plan builds

The long run grows by 1 to 2 miles at a time, which matches the Utah guidance of adding one to two miles per week. Weekly mileage climbs slowly too. In a study of 874 novice runners, those who increased their weekly distance by more than 30% over two weeks appeared more vulnerable to distance-related injuries than those who added under 10%. The difference was not statistically significant, and the study was exploratory and looked at newer runners, but it supports the slow build. Apart from the return after each lighter week, this plan never raises mileage by 30% or more over two weeks.

Weeks 4, 8 and 12 are cutback weeks: about 20 to 28% less mileage and a shorter long run. Rush notes that nearly all training plans include days off and cutback weeks with reduced mileage. Don't use them to catch up on missed miles.

The peak is 42 miles in week 13, with a 20-mile long run. For context, in the 92-plan analysis the plans whose peak week was 65 to 90 km (about 40 to 56 miles) averaged about five runs a week, and their longest run averaged 32.5 km, about 20.2 miles. Lower-volume plans topped out at 30.9 km (19.2 miles) on average, higher-volume ones at 35.2 km (21.9 miles). So a 20-miler at 42 miles a week is typical, not extreme. The authors are clear that published plans describe common practice, not proven effectiveness.

More mileage does tend to go with faster marathons. A survey study of 2,303 recreational runners found that the predicted difference in marathon time between training 50 and 30 miles a week was about 25.5 minutes for men and 31.7 minutes for women. That is not a reason to add miles mid-plan. It is a reason to keep running after this marathon, so your next block starts higher.

Fueling on the long runs

From the 12-mile run in week 6, treat every long run as fueling practice. A review in Sports Medicine found that 30 to 50% of athletes regularly have gut problems during exercise, argues that the gut adapts with training, and stresses practicing your race nutrition strategy in training. For efforts beyond about two hours, it suggests up to about 90 grams of carbohydrate per hour from a mix of carbohydrate types, and warns that more than 60 grams an hour from a single sugar source is likely to cause problems. Build up toward your own amount gradually, with the products you'll race with.

The marathon-pace segments are the best place to test this, because the stomach often handles fuel differently at race speed than at long-run pace. The days before the race are covered in our guide to carb loading for a marathon. If you have diabetes or a digestive condition, plan your fueling with your doctor or a registered dietitian.

The three-week taper

After the 20-miler, mileage drops for three straight weeks: 42, 32, 22, then 11 plus the race. This follows Cleveland Clinic's guidance to reduce mileage two weeks before the race by 25 to 50% versus the previous week, then cut it roughly in half in race week.

It also follows the best result in a study of 158,117 recreational marathoners' training logs: a strict three-week taper, where mileage falls each week to race day, was associated with a median finish about 5.5 minutes (2.6%) faster than a minimal one-week taper. Most runners in the study tapered less strictly, often letting one taper week creep back up. The short marathon-pace segments stay in so your legs remember the pace, but keep everything else easy.

When the plan meets real life

• Missed a few days? Don't make up the miles. Pick up at today's date.
• Missed a week or more? Repeat the last week you completed, then continue. If that pushes your 20-miler closer than three weeks to race day, cap the long run at 18 instead.
• Sick? Rest until you are well, then return with a lighter week.
• Pain that changes your stride or gets worse as you run? Stop and see a doctor or physical therapist. Rush's advice for ordinary aches and fatigue is to take the day off, even if a run is on the schedule.