Sub-four is the most popular goal in marathon running, and it is popular for a good reason: it is genuinely hard and genuinely achievable. It sits at the point where finishing is no longer the challenge and the distance has to be raced.
This guide covers what the number actually demands — the pace, the fitness that supports it, the training paces that build it and the way to run the day itself.
The number: 9:09 per mile
Four hours across 26.2 miles is 9:09 per mile, or 5:41 per kilometre. Those seconds matter — nine seconds a mile over a marathon is nearly four minutes, which is the difference between 3:59 and 4:03.
| Checkpoint | Elapsed time at even pace |
|---|---|
| 5K | 28:26 |
| 10K | 56:53 |
| Half marathon | 2:00:00 |
| 15 miles | 2:17:18 |
| 30K | 2:50:38 |
| 20 miles | 3:03:04 |
| 23 miles | 3:30:32 |
| Finish | 4:00:00 |
The halfway split is the one to internalise: 2:00:00 exactly, at even pace. Going through in 1:57 feels like insurance and is usually the opposite — three minutes banked before mile thirteen is three minutes borrowed from mile twenty-three at a punitive rate of interest. Even splits, or a minute or so on the conservative side, is what a sub-4 usually looks like from the inside.
Are you actually close?
Before building a plan around the number, check whether the number is the right one. Using the same prediction model behind the Verus race time predictor, a four-hour marathon is broadly equivalent to:
| Distance | Equivalent time | What it tells you |
|---|---|---|
| 5K | 25:01 | Quick to test, but the least reliable predictor of a marathon. Treat it as a floor, not a forecast. |
| 10K | 52:10 | A good mid-block check. If you are well outside this eight weeks out, adjust the goal rather than the training. |
| Half marathon | 1:55:07 | The best single predictor. A half in this range on marathon training is the strongest evidence you will get. |
The mileage caveat
These equivalents assume training that supports the distance. A runner with a 1:55 half off 20 miles a week is not in sub-4 shape — the half says the speed is there, and the marathon asks whether the endurance is. The most common sub-4 failure is a runner fast enough for the pace and not durable enough for the duration.
The paces to actually train at
This is where most sub-4 attempts go wrong, and the error is almost always the same: running easy days too hard, which caps how much quality work is possible and accumulates fatigue without the fitness that should come with it.
A four-hour marathon corresponds to a VDOT of about 37.9 on the Daniels-Gilbert model that the Verus training pace calculator computes. That produces the following zones.
| Zone | Per mile | Per km | What it is for |
|---|---|---|---|
| Easy | 9:49-11:44 | 6:06-7:17 | The majority of your weekly mileage, including long runs. Conversational. |
| Marathon | 8:53-9:43 | 5:31-6:02 | Race-pace work inside long runs. Your 9:09 target sits in this band. |
| Threshold | 8:33-8:58 | 5:19-5:34 | Tempo runs and cruise intervals — one session a week. |
| Interval | 7:43-8:03 | 4:48-5:00 | VO2max reps of 3-5 minutes. Occasional rather than weekly. |
| Repetition | 6:40-7:25 | 4:08-4:37 | Short, fast reps with full recovery, for economy and speed. |
Look at the easy band. Nearly ten to nearly twelve minutes a mile, for someone targeting nine minutes. That gap is the single most important number on this page, and it is the one people refuse to believe. Easy running that slow is what makes it possible to do enough of it.
What a sub-4 training week looks like
Four to five runs a week is the normal shape. The specifics vary; the structure rarely does.
- Long run, building towards 18-20 miles, run at easy pace — with segments at marathon pace in the later weeks of the block.
- One threshold session: 20-40 minutes of continuous tempo, or cruise intervals with short recoveries.
- Two or three easy runs, genuinely easy, one of which can carry a few strides at the end.
- One rest day at minimum, and a lower-volume week roughly every fourth week.
- Optional fifth run once the base is solid, added as easy volume rather than another hard session.
The marathon-pace long run is the session that separates a sub-4 build from a finish-the-thing build. Running the last six or eight miles of a long run at 9:09, on legs that already have twelve miles in them, is the closest rehearsal available for what the race actually asks.
Running the day
- 1 First three miles: 10-15 seconds a mile slower than target. This is the only section where holding back is correct, and it costs you almost nothing.
- 2 Miles 4-13: settle onto 9:09 and stop thinking about it. Take every drink station.
- 3 Miles 14-20: hold. The temptation to push when you feel good at eighteen is the classic sub-4 error.
- 4 Miles 20-23: the real race. Focus on form and effort; accept a small controlled slowdown rather than fighting it into a large one.
- 5 Miles 23-26.2: if you paced it, there is something here. This is where a sub-4 is finished rather than where it is lost.
Fuel is not optional at this pace
Four hours is long enough that glycogen becomes the limiting factor rather than fitness. Practise your carbohydrate intake on long runs — not on race day — and take it early and regularly rather than waiting until you need it. By the time you feel empty, it is an hour too late to fix.
The two things that can decide it before you start
Conditions first. Air temperature plus dew point in Fahrenheit is the coaching rule of thumb: under 100 there is no real penalty, 120-130 costs 1-2%, and 140-150 costs 3-4.5%. Three per cent of four hours is over seven minutes, so a warm race day can put sub-4 out of reach for a runner who was genuinely ready for it. Knowing that in advance lets you switch to an effort-based plan rather than discovering it at eighteen miles.
Course second. UK marathon profiles vary more than their marketing suggests — Manchester at around 121ft of elevation gain and Chester at around 249ft are meaningfully different propositions from Brighton at around 477ft with a climb in the first kilometre. If sub-4 is the whole point of the entry, the course is part of the decision.
If you miss it
Most people who break four hours did not do it on the first attempt. A 4:06 is not a failed marathon; it is a marathon that tells you precisely what to change — usually the first three miles, occasionally the fuelling, sometimes just the weather.
The runners who get there are, overwhelmingly, the ones who kept the target and ran another one. If it helps to make that public rather than private, a Verus profile is built for exactly this: the goal, the date, and the gap closing between attempts where other people can see it.