Sub 4 Hour Marathon: Pace, Splits, 16-Week Training Plan, and Fueling
A sub 4 hour marathon means 5:41 per km (9:09 per mile) for 42.2 km, the same pace as a sub 2 half. Here is the pace and split table, a readiness check, a 16-week plan with marathon-pace long runs, the taper, a race-day pacing plan, and the fueling that decides whether you hold pace after 30 km.
Quick answer
Sub 4 marathon pace is 5:41 per km or 9:09 per mile, which is the same pace as a sub 2 hour half marathon. Aim for 5:34 to 5:36 per km (8:58 to 9:01 per mile) so you finish around 3:55 to 3:56 and have room for the extra distance your watch will measure. You are likely ready if you can run a half marathon in about 1:52 to 1:55. Train for 16 weeks, building from about 40 to 70 km per week, with long runs up to 32 km and marathon-pace blocks in the long run. On race day, take 60 to 75 g of carbs per hour from the start, which is a gel every 25 to 30 minutes plus some sports drink, after 36 to 48 hours of eating 8 to 10 g of carbs per kg.
Sub 4 marathon pace is 5:41 per km, or 9:09 per mile. That is exactly the same pace as a sub 2 hour half marathon, held for twice as long. Most runners who get there have a half marathon of about 1:52 to 1:55, follow 16 weeks of training that builds to 60 to 70 km a week with long runs up to 32 km, and treat fueling as part of the plan. That last part matters more than most people think. When sub 4 slips away by a few minutes, it is usually lost after 30 km, when the fuel runs low and the pace fades.
This guide covers the pace and split table, a readiness check, a 16-week plan with every key session, the paces for each run, a sample week with daily carbs, the taper, a race-day pacing plan, and a fueling plan built to hold 5:36 per km all the way to the finish.
Sub 4 Marathon Pace and Splits
| Split | 5:41 per km (the limit) | 5:40 per km | 5:34 per km (3:55 buffer) |
|---|---|---|---|
| Pace per mile | 9:09 | 9:07 | 8:58 |
| 5 km | 28:25 | 28:20 | 27:50 |
| 10 km | 56:50 | 56:40 | 55:40 |
| 15 km | 1:25:15 | 1:25:00 | 1:23:30 |
| 20 km | 1:53:40 | 1:53:20 | 1:51:20 |
| Halfway (21.1 km) | 1:59:54 | 1:59:33 | 1:57:27 |
| 25 km | 2:22:05 | 2:21:40 | 2:19:10 |
| 30 km | 2:50:30 | 2:50:00 | 2:47:00 |
| 35 km | 3:18:55 | 3:18:20 | 3:14:50 |
| 40 km | 3:47:20 | 3:46:40 | 3:42:40 |
| Finish (42.2 km) | 3:59:48 | 3:59:06 | 3:54:53 |
The 5:41 column has only 12 seconds of margin, and that disappears fast. Marathon courses are measured on the shortest line, and many runners cover 42.6 to 42.8 km by weaving, running wide on corners, and moving to the side at water stations. At 5:41 per km, 42.6 km takes 4:02:07. At 5:34 per km, even 42.8 km takes 3:58:15. That is why the target in this plan is 5:34 to 5:36 per km. On race day, check your time at each km marker, not the pace on your watch.
Are You Ready? Your Half Marathon Tells You
A sub 2 half and a sub 4 marathon share a pace, but they are not equal. The Riegel formula scales a race time up to a longer distance. It predicts well up to the half marathon, but a study of 2,303 recreational runners found it was 10 minutes or more too fast at the marathon for half of them. So treat the marathon predictions below as a best case, not a promise.
| Recent half marathon | Riegel marathon prediction | What it means for sub 4 |
|---|---|---|
| 1:50 | 3:49:21 | Ready. You have room for a warm day or a bad patch. |
| 1:52 | 3:53:31 | A good sign. Target 3:55 with this plan. |
| 1:53 | 3:55:36 | Realistic with full training and fueling. |
| 1:55 | 3:59:46 | On the edge. Everything has to go right. |
| 1:58 | 4:06:01 | A stretch. Aim for about 4:05 this time. |
| 2:00 | 4:10:12 | A sub 2 half is not yet a sub 4 marathon. |
Other equivalents for a 4:00 marathon are a 5 km of about 25:00 and a 10 km of about 52:10, but shorter races predict the marathon less well than a half does. Before week 1, you should be running 4 to 5 times a week, about 35 to 40 km (22 to 25 mi) per week, with a long run of 14 to 16 km that feels easy.
Your Training Paces
| Run type | Pace per km | Pace per mile | How it should feel |
|---|---|---|---|
| Easy | 6:30 to 7:10 | 10:28 to 11:32 | Relaxed. You can talk in full sentences. |
| Long run (easy parts) | 6:20 to 7:00 | 10:12 to 11:16 | Steady and comfortable |
| Marathon pace (MP) | 5:35 to 5:40 | 8:59 to 9:07 | Controlled. Should feel easy for the first hour. |
| Threshold | 5:15 to 5:25 | 8:27 to 8:43 | Comfortably hard. A few words at a time. |
| Intervals | 4:50 to 5:00 | 7:47 to 8:03 | About 5 km race pace. Hard but even. |
The 16-Week Sub 4 Marathon Training Plan
Run 5 times a week. Each week has one key workout and one long run, and everything else is easy. Start key workouts with 2 to 3 km easy and finish with 2 km easy. Weeks 4, 8, and 12 are lighter so your body can absorb the work. The half marathon in week 8 is your real readiness test.
| Week | Weekly km (mi) | Long run | Key workout |
|---|---|---|---|
| 1 | 40 (25) | 16 km easy | 5 x 1 km at threshold, 90 seconds jog |
| 2 | 44 (27) | 18 km easy | 3 x 2 km at threshold, 2 minutes jog |
| 3 | 48 (30) | 20 km easy | 6 x 800 m at interval pace, 2 minutes jog |
| 4 (lighter) | 40 (25) | 16 km, last 4 km at MP | 5 km time trial or parkrun |
| 5 | 52 (32) | 22 km easy | 3 x 3 km at threshold, 2 minutes jog |
| 6 | 56 (35) | 24 km, last 6 km at MP | 5 x 1 km at interval pace, 2 minutes jog |
| 7 | 60 (37) | 26 km easy | 12 km with 8 km at MP |
| 8 (lighter) | 48 (30) | Half marathon race. Goal: 1:52 to 1:55. | Easy running only around the race |
| 9 | 60 (37) | 28 km easy | 4 x 2 km at threshold, 2 minutes jog |
| 10 | 64 (40) | 24 km with 12 km at MP | 6 x 1 km at interval pace, 2 minutes jog |
| 11 | 66 (41) | 30 km easy | 14 km with 10 km at MP |
| 12 (lighter) | 52 (32) | 20 km easy | 3 x 3 km at threshold, 2 minutes jog |
| 13 (peak) | 70 (43) | 32 km easy, or 3 h 30 min, whichever comes first | 5 x 1 km at interval pace, 2 minutes jog |
| 14 | 62 (39) | 26 km with 14 km at MP (dress rehearsal) | 3 x 2 km at threshold, 2 minutes jog |
| 15 (taper) | 48 (30) | 19 km with 8 km at MP | 4 x 1 km at threshold, 2 minutes jog |
| 16 (race week) | About 20 + race | The race | 6 km with 3 km at MP early in the week |
Use week 8 to set your race pace. A half of 1:52 or faster: race at 5:34 to 5:36 per km. A half of 1:53 to 1:55: start at 5:38 to 5:40 and only speed up after 30 km if you feel good. A half slower than 1:57: 4:05 is a strong and realistic goal this time.
Marathon-Pace Long Runs: The Sessions That Matter Most
The long runs in weeks 6, 10, 14, and 15 put marathon pace on tired legs. They teach you what 5:36 per km feels like after 90 minutes of running, and they are the best place to practice race fueling. Eat your race breakfast, take the same gels at the same times you plan to use in the race, and drink from a bottle or belt. The week 14 run, with 14 km at MP, is your dress rehearsal. Wear your race kit and shoes, start at your race start time if you can, and note how your stomach handles 60 to 75 g of carbs per hour.
Keep the easy long runs easy. Your 32 km run in week 13 is about time on your feet, not speed. At 6:30 to 7:00 per km it takes about 3 h 28 min to 3 h 44 min, so stop at 3 h 30 min if you are not done. Fuel it like race day: going long without carbs makes recovery slower and teaches your gut nothing.
A Sample Week With Daily Carbs (Week 10)
Your food should rise and fall with your training. Guidelines set daily carbs by body weight: about 3 to 5 g per kg on light days, 5 to 7 g per kg for about an hour of training a day, and 6 to 10 g per kg for 1 to 3 hours. Here is week 10 for a 70 kg (154 lb) runner.
| Day | Session | Carbs per kg | Carbs at 70 kg |
|---|---|---|---|
| Monday | Rest | 3 to 5 g | 210 to 350 g |
| Tuesday | 12 km with 6 x 1 km at interval pace | 5 to 7 g | 350 to 490 g |
| Wednesday | 10 km easy | 5 to 6 g | 350 to 420 g |
| Thursday | 10 km easy plus 6 strides | 5 to 6 g | 350 to 420 g |
| Friday | Rest | 3 to 5 g | 210 to 350 g |
| Saturday | 8 km easy | 6 to 7 g | 420 to 490 g |
| Sunday | 24 km with 12 km at MP (about 2 h 27 min) | 7 to 8 g | 490 to 560 g, plus 60 to 75 g per hour during the run |
Add 1.2 to 2.0 g of protein per kg per day, about 85 to 140 g at 70 kg, with 20 to 40 g after the key workout and the long run. Most runners who feel flat in weeks 10 to 13 are simply not eating enough carbohydrate for the volume. Mavr sets these targets each day from your synced training, so a moved long run or a swapped workout changes your food too. The training diet guide linked at the end has full meal plans.
The Taper: Weeks 14 to 16
The biggest week and the 32 km run come 3 weeks out. After that, volume drops: 62 km, then 48 km, then about 20 km plus the race. Keep some marathon pace and threshold running so your legs stay sharp, and keep running 4 to 5 times a week. Race week example for a Sunday race: Tuesday 6 km with 3 km at MP, Wednesday 6 km easy, Friday 5 km easy, Saturday 3 km very easy with 4 strides. Do not eat less because you are running less. Your body is repairing and refilling glycogen, and the carb load starts on Friday.
Race-Day Pacing Plan
Run the first 5 km a little slow while the crowd thins, settle into 5:36 per km, and hold it until 40 km. The first half should feel easy. If it feels like work at 15 km, you are going too fast. Banking time is the classic sub 4 mistake: a 5:20 per km first half almost always costs more than it saves.
| Section | Pace per km | Clock time at the end |
|---|---|---|
| Start to 5 km | 5:42 | 28:30 |
| 5 to 10 km | 5:36 | 56:30 |
| 10 to 15 km | 5:36 | 1:24:30 |
| 15 to 21.1 km (halfway) | 5:36 | 1:58:39 |
| 21.1 to 30 km | 5:36 | 2:48:30 |
| 30 to 35 km | 5:36 | 3:16:30 |
| 35 to 40 km | 5:36 | 3:44:30 |
| 40 km to finish | 5:30 if you can | 3:56:34 |
If you run with a 4:00 pace group, stay a little ahead of it. Pace groups often aim to finish right at 3:59, and crowded water stations around the group cost time.
Fueling: Where Sub 4 Is Usually Won or Lost
A marathon at 5:36 per km burns more carbohydrate than your muscles and liver can store. More than two in five marathon runners run low on glycogen and hit the wall. In an analysis of more than 4 million marathon results, about 28 percent of men and 17 percent of women slowed sharply late in the race, usually after 32 km (20 miles), and ran that stretch about 40 percent slower than their earlier pace. You do not need a collapse that big to miss sub 4. Running just 10 percent slower over the last 10 km costs about 5 minutes and 40 seconds, which is more than your whole buffer.
Two things push the wall back: starting with full glycogen and taking in carbohydrate from the first half hour. In a study of 257 London Marathon runners, those who ate more than 7 g of carbs per kg the day before ran faster and held their pace better. During a race of 3 to 4 hours, aim for 60 to 75 g of carbs per hour. Above 60 g per hour, use products that mix glucose and fructose, because they are absorbed through two routes and sit better in the gut.
| When | What to do | Target (70 kg runner) |
|---|---|---|
| 36 to 48 hours before | Carb load: rice, pasta, bread, potatoes, juice, low fiber | 8 to 10 g per kg per day (560 to 700 g) |
| The night before | Normal-sized, familiar carb dinner, eaten early | About 2 to 3 g per kg |
| 3 to 4 hours before | Breakfast: bagels with jam, banana, juice | 1.5 to 3 g per kg (105 to 210 g) |
| 45 to 60 minutes before | Usual coffee, if you drink it | About 3 mg caffeine per kg (210 mg) |
| 10 to 15 minutes before | One gel with water | 20 to 30 g |
| During the race | Gel every 25 minutes plus sips of sports drink | 60 to 75 g per hour |
| Gel | Race time | About km (at 5:37 per km) |
|---|---|---|
| 1 | 0:25 | 4.5 |
| 2 | 0:50 | 9 |
| 3 | 1:15 | 13.5 |
| 4 | 1:40 | 18 |
| 5 | 2:05 | 22 |
| 6 | 2:30 | 27 |
| 7 | 2:55 | 31 |
| 8 | 3:20 | 35.5 |
Eight gels of 25 to 30 g give 200 to 240 g of carbohydrate. Add 40 to 60 g from sports drink at aid stations and you reach 240 to 300 g, or about 60 to 75 g per hour over the race. If you prefer a gel every 30 minutes, choose larger gels of 30 to 40 g. Do not wait until you feel low: by 30 km, it is too late to catch up. Practice this exact plan on at least four long runs, starting with 40 to 50 g per hour if you are new to it and building up. Gut problems on race day almost always come from doing something new.
Enter your goal time, body weight, preferred gel, and the weather. Get your carb load target, race breakfast, a gel schedule by km, and fluids and sodium per hour. Free, and it takes about a minute.
Frequently Asked Questions
What is sub 4 marathon pace?
Sub 4 marathon pace is 5:41 per km or 9:09 per mile. Because many runners cover 42.6 to 42.8 km on race day, aim for 5:34 to 5:36 per km (8:58 to 9:01 per mile), which gives about 3:55 to 3:56.
What half marathon time do I need for a sub 4 marathon?
About 1:52 to 1:55. The Riegel formula says 1:55 equals a 4:00 marathon, but it is often too optimistic for recreational runners, so a half of 1:52 or faster is a safer sign.
How many km a week do I need to run for a sub 4 marathon?
Most runners peak at 60 to 70 km (37 to 43 mi) a week. This plan builds from 40 km in week 1 to 70 km in week 13, over 5 runs a week.
How long should my longest run be for a sub 4 marathon?
About 30 to 32 km, run easy, 3 to 4 weeks before the race. Cap it at about 3 h 30 min. Longer runs add fatigue without much extra benefit.
How many gels do I need for a sub 4 marathon?
Usually 8 during the race plus 1 before the start, taken every 25 minutes, with some sports drink at aid stations. That gives about 60 to 75 g of carbs per hour.
Is sub 4 marathon pace the same as sub 2 half marathon pace?
Yes, both are 5:41 per km or 9:09 per mile. But a 2:00 half predicts a marathon of about 4:10, so you usually need a faster half, plus the long runs and fueling, to break 4 hours.
Sources
Sources and official references
- 1.Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and ACSM: Nutrition and Athletic PerformanceJournal of the Academy of Nutrition and Dietetics (Thomas et al., 2016) · Daily carbs by training load, carb loading for events over 90 minutes, pre-event meals of 1 to 4 g/kg, and carbs per hour during long events
- 2.Pre-race Dietary Carbohydrate Intake Can Independently Influence Sub-elite Marathon Running PerformanceInternational Journal of Sports Medicine (Atkinson et al., 2011) · London Marathon runners eating more than 7 g/kg the day before ran faster and held pace better
- 3.Metabolic Factors Limiting Performance in Marathon RunnersPLOS Computational Biology (Rapoport, 2010) · Glycogen stores limit marathon performance; more than two fifths of runners hit the wall
- 4.How Recreational Marathon Runners Hit the Wall: A Large-Scale Data Analysis of Late-Race Pacing Collapse in the MarathonPLOS ONE (Smyth, 2021) · In over 4 million race records, 28 percent of men and 17 percent of women slowed sharply late in the race, typically after 20 miles
- 5.A Step Towards Personalized Sports Nutrition: Carbohydrate Intake During ExerciseSports Medicine (Jeukendrup, 2014) · Carbohydrate per hour scaled to event duration, with glucose and fructose mixes for higher intakes
- 6.Contemporary Nutrition Strategies to Optimize Performance in Distance Runners and Race WalkersInternational Journal of Sport Nutrition and Exercise Metabolism (Burke et al., 2019) · Carb-rich eating before the race and practiced in-race carb and fluid plans for marathon runners
- 7.An Empirical Study of Race Times in Recreational Endurance RunnersBMC Sports Science, Medicine and Rehabilitation (Vickers and Vertosick, 2016) · The Riegel formula was 10 minutes or more too fast at the marathon for half of 2,303 recreational runners
Prompt ideas for AI assistants
- “My half marathon best is 1:54. Can I run a sub 4 hour marathon?”
- “How many gels do I need for a 3:55 marathon at 70 kg?”
- “What should my marathon pace long runs look like for sub 4?”
Mavr syncs your marathon plan from Garmin, Strava, TrainingPeaks, Runna, Intervals.icu or Apple Health and sets your carbs for every training day, your carb load, and a gel plan for your goal pace.
Written by
Mavr Sports Nutrition Team
The Mavr sports-nutrition team translates peer-reviewed endurance research (Jeukendrup, Burke, the ISSN) into daily fueling for runners and triathletes.