Four hours is the marathon's most crowded finish line for a reason. It is fast enough to demand respect and slow enough to be within reach of almost any runner willing to train. The math is simple: 9:09 per mile (5:41 per km) is your ceiling. The strategy is where people blow it.
Here are three ways to get there. Two are the textbook and the pro playbook. The third is what I actually do, which I do not necessarily recommend, but I will not pretend I run these things by the book either. Every plan below opens live in the calculator, so you can tap it, tweak it, and make it yours.
Plan 1: The Textbook Even Split
Run 9:05s. All of them.
Every mile at 9:05 · finish 3:58:00 · 2:00 of cushion
The most boring plan in running and the one with the best success rate. Lock in a pace a few seconds under your ceiling, run it from the gun, and trust it when it feels insultingly easy at mile 6. It is supposed to feel easy at mile 6. The runners who bank time in the first half give it back with interest in the second, and the ones who run metronome splits pass them all after mile 20.
Open this plan in the calculatorPlan 2: The Pro-Style Negative Split
Patient for 20, brave for 10K.
20 mi at 9:12, last 10K at 8:45 · finish 3:58:25
This is how the best races at every level are run: start a touch slower than goal pace, spend 20 miles collecting runners' souls being patient, then squeeze the last 10K. The hard part is not the fast finish. It is having the discipline to run 9:12 at mile 3 when your legs are begging for 8:40. If you have done the long runs and the mileage, this plan turns the last 10K from a death march into the best part of your race.
Open this plan in the calculatorPlan 3: The Hold-On Method
My confession: reasonable half, then survive.
13 mi at 8:45, miles 14-20 at 9:05, last 10K at 9:30 · finish 3:56:25
Here is the truth about how I run marathons. I race a lot of 5Ks and half marathons. My 5K pace is around 7:30. What I mostly do not do is the 20-mile training run, or all the runs that would really get me where I need to be. So my race plan is built around that honesty.
I go out and run a reasonable half marathon, somewhere in the 8:30 to 9:00 range, nothing heroic. After 13, the job changes: do not slip past 9:00 if I can help it. As 20 gets close, the deal I make with myself is to stay near 9:30. And then I hold on and find out what is left in the tank. Some days that is a strong last 10K and a great finish. Some days the tank has other opinions.
I am not recommending this. Sergeant Stride will warn you about the fast start the moment you open my plan, and he is right. But if your training looks like mine, short-race fit and long-run light, at least plan the fade on purpose instead of being surprised by it. That is the difference between holding on and falling apart.
Open my plan in the calculatorWhich plan is yours?
It depends on who you are as a runner, and being honest about that is the whole game. If you have done the mileage and the long runs, Plan 1 or Plan 2 will serve you well. If you are a short-distance specialist trying to gut one out on 5K fitness, you are living in Plan 3 territory whether you admit it or not, so admit it and plan for it.
We wrote up the runner types and the math behind all of this, including why standard race predictors overestimate runners who skip long runs, in How We Built It. Find your type, set the profile slider honestly, and let the calculator tell you the truth before mile 22 does.