Sub 4 hour marathon pace: splits, training and the second half

Sub 4 hour marathon pace is 5:41 per kilometer, or 9:09 per mile. Hold that for 42.195 km and you finish in 4:00:00 exactly, which is not sub-4. So the real target is a few seconds quicker: around 9:05 per mile or 5:38 per km.

Sub-4 is the most famous amateur marathon goal for a reason. It's round, it's respectable, and it's hard in a very specific way: the pace feels easy for 15 miles and then the marathon starts. This post covers the pace for a sub 4 hour marathon, full splits, what fitness usually sits under it, the long runs and sessions that matter, a week that keeps your lifting, and how to run the second half instead of surviving it. Plan it by hand or use an app that balances mileage with gym days.

What is a sub 4 hour marathon pace?

The math: 4 hours is 14,400 seconds. Divided by 42.195 km, that's 341 seconds, or 5:41 per km. Multiply by 1.609344 and it's 549 seconds per mile: 9:09.

Different goal? Use a free pace calculator and the same logic. The conversion tables and goal paces for every common race are in the hub on pacing your goal time, and these numbers match it.

Pace for a sub 4 hour marathon, with a buffer

Aim for 9:05 per mile or 5:38 to 5:39 per km. That's about two minutes of buffer, which sounds generous until you account for weaving around people, aid stations and the extra few hundred meters almost everyone runs over 42.195 km.

Sub-4 marathon splits

Even pace for exactly 4:00:00:

Halfway at 2:00:00 on the nose. You want to be slightly under it, not well under it.

Two 2-hour halves, back to back

Sub-4 pace is identical to 2-hour half marathon pace. That's the clearest way to see the size of the job: run a sub-2 half, then immediately run another one.

For context, RunRepeat's percentile calculator puts the median half marathon finish at 2:14:59 overall, 1:59:48 for men and 2:24:03 for women. So the first half of a sub-4 marathon is roughly the men's median half time, about 15 minutes faster than the overall median half, and then there are 13.1 more miles.

If you've already run a 2-hour half, half marathon 2 hour pace explained covers the same 9:09 per mile from the other side. Being able to hold it for 13.1 miles is a good sign. It isn't proof you can hold it for 26.2.

What fitness a sub-4 marathon usually takes

Coaching practice, not a formula. Runners who break 4 hours usually have:

• ›A half marathon well under 2:00. If 2:00 is your best half, sub-4 pace is your half race pace, and that's too fast for a marathon. Plug your recent half into a calculator; if it predicts sub-4 with room, the speed is there.
• ›Long runs that have reached 18 to 20 miles. Several of them, at easy pace, without falling apart.
• ›Four or five runs a week for months. Plans aimed at sub-4 commonly peak somewhere around 30 to 45 miles a week. Some runners get there on less with a long background, but the marathon is honest about missing mileage.

Speed is rarely the limiter at this pace. Durability is. That's why the training below leans on long runs and steady running rather than track sessions.

Key workouts for a sub-4 marathon

1. The time-on-feet long run

Build the weekly long run gradually toward 18 to 20 miles at easy, conversational pace, with a cutback week every third or fourth week. This is the session that matters most for sub-4. Practice eating and drinking exactly what you'll use on race day.

2. The back-half long run

Every second or third long run in the last eight weeks: 14 to 16 miles, with miles 10 to 14 at 9:05 per mile, then easy to finish. It teaches you to hit goal pace on tired legs, which is the entire problem of a sub-4.

3. The midweek steady run

6 to 8 miles, with the last third at marathon pace. Short enough to recover from, long enough to make 9:05 per mile feel automatic.

4. Tempo or hills, once a week early

Early in the build, 20 to 25 minutes of tempo (RPE 7–8), or 8 × 60 seconds up a hill. It raises your ceiling so marathon pace feels further below it. As race day gets closer, the marathon-pace work takes over this slot.

A sub-4 marathon training week

Four runs, two lifts, mid-build. In the peak weeks, one well-placed lift is often enough.

Rules:

• ›Lower-body lifting stays two days from the quality run and as far from the long run as the week allows. Monday is five days before Saturday.
• ›The long run is the most important session. If something has to give in a busy week, it isn't this.
• ›Keep the lifting. 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, and the authors suggest two to three sessions a week. A few hard sets of squats or deadlifts, single-leg work, calves and hips. Maintain, don't chase PRs.

Sub 4 hour marathon pacing: run the second half

The first half of a sub-4 attempt feels easy. That's the trap.

In an analysis of millions of marathon results, Smyth (2021) found 28% of male and 17% of female recreational runners hit the wall, defined as a sustained period of slowing in the latter stages of the race. A lot of those slowdowns start with an optimistic first half.

The plan:

• ›First 10 km: 5:40 to 5:45 per km. About 57 minutes at 10 km. Slower than you want. It's meant to be.
• ›10 km to 30 km: 5:38 per km, or 9:05 per mile. Lock in. Use the mile or kilometer markers, not just your watch.
• ›Halfway: 1:59:00 to 2:00:00. If you're at 1:55, you've borrowed time at a terrible interest rate.
• ›30 km to the finish: hold. If you have something at 35 km, use it then and not before.

Pace groups are useful if your race has one. Run with the 4:00 group only if you've checked its pace against the markers in the first few miles, and ideally sit just behind it rather than racing the pacer.

Fuel from early on, in the amounts and products you practiced on long runs. The body you have at mile 20 depends on what you did at mile 5.

Taper and race week

Cut volume over the last two to three weeks and keep a few short marathon-pace efforts. Last long run about three weeks out. Last real lower-body session about ten days out. Then nothing new: not shoes, not breakfast, not a gel flavor someone handed you at the expo.

Where sub-4 sits on the ladder

The 5K is a decent speed check. A guide to 20 minute 5k pace puts it at 4:00 per km, and a guide to 25min 5k pace at 5:00 per km. If your 5K is around 25 minutes, the speed for 5:41 per km is there, and the job is endurance.

If sub-4 goes well, what pace is a 3 30 marathon? 4:59 per km, and it asks for more mileage. Much further up, what pace is a 2 55 marathon? 4:09 per km, 6:40 per mile. At the other end, 4:30 marathon pace and training works out at 6:24 per km, and what pace is a 5 hour marathon? 7:07 per km, or 11:27 per mile. Every one of those is still a marathon.

How exrsz handles a sub-4 marathon

exrsz builds a periodized marathon plan from your goal, schedule, level and equipment, with running and lifting in one plan so leg day stays away from the long run. It adapts each week to how you actually trained and reshuffles missed sessions so the build still lands on race day.

FAQ

What pace is a sub 4 hour marathon?

5:41 per kilometer or 9:09 per mile gets you exactly 4:00:00. To finish under, aim for about 9:05 per mile or 5:38 per km.

What is the pace for a sub 4 hour marathon per km?

5:41 per km for exactly four hours. Running 5:38 per km finishes in about 3:57:42.

What half marathon time do I need for a sub-4 marathon?

You want a recent half comfortably under 2:00, because 2:00 is exactly sub-4 pace for half the distance. How much under depends on your endurance, so use calculator predictions as a starting point.

How many miles a week do you need for a sub-4 marathon?

There's no fixed number, but plans aimed at sub-4 commonly peak around 30 to 45 miles a week across four or five runs. The long run matters more than the weekly total.

Why do people miss sub-4 in the second half?

Mostly pacing and fueling. In Smyth's 2021 analysis, 28% of male and 17% of female recreational runners hit the wall, so start conservatively and fuel the way you practiced.