How to Pace a Marathon: The Strategy That Makes the Difference in the Final 10 Kilometres

Most runners don't have a speed problem in the marathon. They have a pacing problem.

I see it regularly with athletes I coach - and I've made the mistake myself. The first 15 kilometres feel easy. The pace feels generous. The crowd is loud, the legs are fresh, and the effort feels well within range. So the pace creeps slightly. Then a little more. By 28 or 30 kilometres, something starts to unravel, and the final 10 becomes a very different race from the one that was planned.

The marathon doesn't reward bravery in the early kilometres. It rewards patience. Understanding how to pace a marathon properly - not just in theory, but in practice, when the atmosphere is pushing you forward and the effort feels manageable - is one of the most valuable skills an endurance runner can develop.

This article explains how to build a marathon pacing strategy that holds together from start to finish.

Why Pacing the Marathon Is Harder Than It Sounds

The challenge with marathon pacing is partly physiological and partly psychological. On the physiological side, the early kilometres of a race feel disproportionately easy because your glycogen stores are full, your muscles are fresh, and the adrenaline of race morning is genuinely affecting your perceived effort. Running 10 seconds per kilometre faster than your target pace feels identical to running at target pace. That gap is invisible until it isn't.

On the psychological side, most runners have trained for months for this event. The pressure to perform, the environment of the race, and the simple fact of feeling good early makes it very difficult to consciously hold back when everything in your body is saying you could go faster.

This is the trap. And it's a trap that claims the majority of recreational marathon runners on race day.

The Case for Even Splits - and Negative Splitting

The most effective marathon pacing strategy for the majority of runners is even pacing - holding a consistent pace per kilometre from start to finish - or a very slight negative split, where the second half of the race is run marginally faster than the first.

The research on this is consistent, and the results from elite performance confirm it. Eliud Kipchoge's world record marathon in Berlin in 2023 was run on remarkably even splits. The fastest recreational marathon runners tend to follow the same pattern, even if they arrive at it through experience rather than data.

The reason even pacing works is aerobic efficiency. When you run at or just below your sustainable aerobic threshold, your body can fuel the effort primarily through fat metabolism supplemented by carbohydrate. When you push beyond that threshold - even marginally, even early - the carbohydrate demand increases significantly, and you begin depleting your glycogen stores faster than planned. At 30 or 32 kilometres, when those stores are running low, the pace that felt easy in kilometre five becomes unsustainable.

A common target is to aim for a first-half that is no more than two to three minutes slower than your second half, or to simply hold the same pace per kilometre throughout. If you run a negative split - even a small one - it is a sign that your pacing was well-judged and your execution held together.

How to Build Your Race Pace Plan

Step one: Know your realistic target time.

This is not your dream time. It is the time your current fitness, your training history, and your recent race results suggest you are capable of. If you completed a half marathon recently, a prediction calculator can give you a reasonable estimate of your marathon potential - but treat it as a guide rather than a guarantee, particularly for a first marathon.

If you haven't raced recently, your long run paces in training give you useful data. Your comfortable long run pace - the pace you can sustain for 25 to 30 kilometres without feeling like you're working - is usually around 45 to 75 seconds per kilometre slower than your potential marathon pace. If that range seems surprising, it should recalibrate your expectations for what target pace actually means.

Step two: Convert your target time to a pace per kilometre.

Divide your target finish time by 42.2. That's your required average pace. Write it down. Put it on your wrist. Know it precisely, because on race day your GPS watch may fluctuate, the route may measure slightly differently from your watch, and the pace on your display needs to be something you can interpret quickly and accurately.

Step three: Build in a first-kilometre buffer.

Start slightly slower than target pace - five to ten seconds per kilometre slower - for the first three to five kilometres. The start of most mass-participation marathons is congested regardless of your wave, and the adrenaline of the start makes holding back feel harder than it is. Beginning conservatively helps the adrenaline settle and gives you a reference point for what target effort feels like before you lock into it.

Step four: Race by effort, not just by watch.

Your GPS watch is a useful tool, not an authority. Course profiles, wind, temperature, and elevation all affect what a given pace costs on a given day. Develop a sense of what your target effort feels like - the breathing rate, the conversational ability, the leg sensation - and use pace as a check on that effort rather than the other way around.

A useful rule: if you can still hold a short conversation at 10 kilometres, you're probably on the right side of the effort. If you can't, reassess.

Common Pacing Mistakes - and What They Cost

Going out too fast. Every extra second per kilometre you run in the first 10 kilometres is borrowed from the final 10. The cost compounds as glycogen depletes and fatigue accumulates. A runner who banks two minutes in the first half rarely holds that margin - they usually lose four or five minutes in the second half.

Chasing the pack. At most events, runners around you in the first 10 kilometres are running at a wide variety of fitness levels. The pace of the crowd is not a reliable guide to your pace. Runners who feel very comfortable early and accelerate past you are often runners who will be struggling by 30 kilometres.

Ignoring the hills. Holding a fixed pace per kilometre on a hilly course is almost always a mistake. On uphills, pace slows and heart rate spikes - maintaining pace requires a disproportionate effort. Instead, maintain effort on hills and allow pace to vary. Use the downhills to recover, not to accelerate aggressively.

Losing focus in the middle kilometres. Kilometres 15 to 30 are where races are often quietly lost. The early excitement has faded, the finish is not yet in sight, and it becomes easy to drift slightly off target pace or to make small adjustments that seem minor but accumulate. Stay disciplined through the middle third.

The Final 10 Kilometres

If your pacing strategy has held, the final 10 kilometres of a marathon should feel hard but manageable. Your legs will be tired. The effort will require concentration. But you should still be running.

If the pacing strategy hasn't held, the final 10 kilometres look different. This is where the marathon earns its reputation for being brutal.

A well-paced race gives you the option to push in the final five kilometres if you have something left. That option only exists if the first 32 kilometres were run with discipline.

One way I frame it with athletes: the goal at halfway is not to feel good. The goal at halfway is to feel controlled. Good feeling early is a warning sign. Controlled feeling is a sign that the strategy is working.

Running the York Marathon in 2024 was my first real focus on marathon pacing

Fuelling and Pacing Are the Same Problem

Pacing and fuelling are not separate decisions. They are the same decision, approached from different angles.

When you go out too fast, you burn more carbohydrate per kilometre. When you deplete your glycogen stores, your pace drops involuntarily - the body has no choice. A good pacing strategy gives your fuelling strategy a chance to work. A poor pacing strategy means that even perfect fuelling execution may not be enough to rescue the second half.

Plan your fuel intake alongside your pace plan. Know at which kilometre markers you'll take on fuel, what you'll take, and how much. This reduces the number of decisions you're making mid-race when fatigue is already affecting your ability to think clearly.

Key Takeaways

Good marathon pacing is a discipline that has to be practised, because the natural instinct on race day - to run quickly when you feel good - is usually the wrong one.

The fundamentals are straightforward: know your realistic target pace, start slightly conservatively, hold an even effort across the first two-thirds of the race, and give yourself the option to push in the final kilometres if the strategy has held.

The marathon rewards patience at the start and rewards it again at the finish. The athletes who run the most satisfying marathons are rarely the ones who ran the fastest first half - they're the ones who ran the most consistent race.

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Steve Barbour is an online running and triathlon coach based in the UK. If you're preparing for a marathon and want structured support with your pacing, training, and race preparation, find out more about coaching at stevebarbour.com/coaching. You can also use the free Marathon Time Predictor and Pace Calculator on Endurance Toolkit.