The quick answer
- 0–10km: Start at a realistic, controlled effort. Avoid banking time with a much faster first 5km.
- 10–21.1km: Find an efficient rhythm and stick to your planned fuelling, not just your watch.
- 21.1–30km: Keep your effort measured. Check conditions and resist the temptation to surge because you feel good.
- 30–40km: Focus on maintaining mechanics, fuelling if tolerated, and managing each kilometre as fatigue rises.
- Final 2.195km: Only lift the effort decisively if you can still sustain your running form.
Race strategy
Is even pacing best for a marathon?
For a road marathon with a reasonably flat course and favourable conditions, even effort and broadly even splits are a sensible starting point for many runners. A modest negative split—running the second half a little faster—can be an option when the target is conservative and conditions cooperate. That is different from promising that everyone should accelerate in the final 10km.
How to race each section
Start with restraint.
The crowds and adrenaline can make your goal pace feel unusually easy. Treat this as a reason to stay disciplined, not to accelerate. Settle towards your planned pace, find space, and avoid repeated weaving that adds distance. If the course begins downhill, resist the urge to chase a quick split at the expense of your legs.
Cue: “Let the race come to me.”Build a rhythm, not a lead.
Stay economical: relaxed shoulders, controlled cadence and small course-aware adjustments. Check effort as well as GPS pace, especially into wind or over hills. Follow the fuelling routine you practised in training; don't wait for a clear energy crash.
Cue: “Smooth, steady, fuel early.”Hold the plan when it still feels good.
Halfway is not permission to launch a long surge. Reassess the weather, whether you've taken enough carbohydrate, and whether your effort is still sustainable. If your target was realistic, the simplest valuable decision may be to continue doing exactly what you're doing.
Cue: “Patient now, strong later.”Protect the second half.
This is where a too-fast start may catch up with you. Think in manageable checkpoints, keep the arms purposeful and avoid tensing your upper body. If speed drops, evaluate effort and symptoms rather than blindly forcing the watch back to its original pace.
Cue: “Stay tall. One kilometre at a time.”Spend what's left—if it's safe.
If you still have good mechanics and control, increase effort through the final kilometres. Finishing strongly may mean accelerating, or simply losing less speed than expected. There is no need to save a dramatic sprint if the final 2km is already taking everything you have.
Cue: “Keep moving. Finish the job.”Example: how to break 3 hours in the marathon
A target of 2:59:00 requires about 4:14.5/km (or 6:49.5/mile) across 42.195km. Targeting 2:59 gives approximately one minute of buffer versus 3:00, without encouraging a reckless start.
| Section | Segment | Elapsed | Race cue |
|---|---|---|---|
| 5 km | 21:13 | 21:13 | Stay on your planned effort |
| 10 km | 21:13 | 42:25 | Stay on your planned effort |
| 15 km | 21:13 | 1:03:38 | Stay on your planned effort |
| 20 km | 21:13 | 1:24:51 | Stay on your planned effort |
| 21.0975 km | 4:39 | 1:29:30 | Stay on your planned effort |
| 25 km | 16:33 | 1:46:03 | Stay on your planned effort |
| 30 km | 21:13 | 2:07:16 | Stay on your planned effort |
| 35 km | 21:13 | 2:28:29 | Stay on your planned effort |
| 40 km | 21:13 | 2:49:41 | Stay on your planned effort |
| 42.195 km | 9:19 | 2:59:00 | Finish |
These are even-pace reference checkpoints rounded to the nearest second, not a promise that 2:59 pacing is suitable for everyone. GPS distance often differs from certified course distance, so follow official kilometre markers where possible. Set your goal from recent training and racing, and rehearse fuelling well before race day.
Fuel from the beginning—not just when you fade
Marathon pacing and fuelling are inseparable. If you run too hard early, you may burn through carbohydrate faster than planned; if you underfuel, keeping the same pace later can become increasingly difficult. Practice carbohydrate intake in long training runs, including how often you take it and how you tolerate fluids or gels.
The World Athletics 2019 nutrition consensus lists roughly 30–60g carbohydrate per hour for events of 1–2.5 hours, and for events lasting longer than 2.5 hours considers higher intakes, up to around 90g/hour, where appropriate and practised. Individual needs vary; higher isn't automatically better if it causes stomach problems. [4]
Simple fuelling decisions for race day
- Practise your gel, drink and carbohydrate schedule during long runs—never experiment with large amounts for the first time on race morning.
- Have a plan for aid stations and know whether your chosen gels require additional water.
- Adjust fluid intake to conditions and personal sweat losses; avoid both substantial dehydration and overdrinking.
- Carbohydrate targets are guidance, not a medical prescription. Seek individual advice if you have a medical condition or a history of severe gastrointestinal issues.
Why the weather can change your perfect pace
A target that is realistic on a cool, flat morning may not be realistic in heat, humidity or substantial headwinds. An analysis of results from multiple major US marathons found performance worsened as conditions became hotter, with meaningful variation across runner ability. [5]
On hot days, pace by sustainable effort rather than blindly forcing cool-weather splits. Uphills and wind may require a slower kilometre; downhills can allow faster splits without extra effort, but excessive downhill aggression can strain your legs. Smart marathon pacing adapts to the course instead of fighting it.
Research & lessons from elite racing
In a 2024 systematic review covering 39 studies across marathon, half-marathon and ultra-distance competition, positive pacing was frequently observed. Observation is not prescription: the fact that runners often slow down does not prove that planning to slow down is optimal. [1]
A separate study of recreational 10km and marathon runners also observed second-half slowdowns in its samples. This strengthens the case for avoiding an overly ambitious first half, rather than aiming for an exact universal positive- or negative-split percentage. [2]
What Kipchoge's 2022 Berlin marathon tells us
Eliud Kipchoge ran 2:01:09 in Berlin in 2022, a world record at the time. World Athletics reported a 59:50 first half. His remaining half therefore took 61:19. Even one of the sport's greatest marathon performances included a positive split. [3]
Kipchoge's two halves — Berlin 2022
The second half was 1 minute 29 seconds slower. Bars begin at zero; longer means more time.
What this does—and doesn't—prove: Kipchoge's extraordinary performance shows that a positive split can coexist with a world-class result. It does not mean a recreational runner should imitate his aggressive opening pace. Your best strategy depends on fitness, fuelling, terrain and conditions.
Common mistakes & how to avoid them
Banking time in the opening 10km
Better approach: Start at a realistic effort rather than far ahead of goal pace.
Taking fuel only once you feel tired
Better approach: Rehearse consistent carbohydrate and fluid intake in long runs and begin early.
Ignoring heat, climbs or wind
Better approach: Protect sustainable effort instead of blindly defending a GPS split.
Treating 35km as the start of the race
Better approach: Small pace and fueling errors can compound long before the final 10km.
Questions runners ask
Quick answers to common questions about pacing a Marathon race.
Should I aim for a negative split in a marathon?
A slight negative split can be a useful plan when your target is realistic, but it is not mandatory. A broadly even effort is often a safer principle than forcing an ambitious acceleration late in the race.
How fast should I run the first 5km?
Close to a sustainable planned average pace, with a sensible allowance for congestion, terrain and adrenaline. Avoid treating early kilometres as an opportunity to gain several minutes.
Why do runners slow after 30km?
Fatigue is multi-factorial: energy availability, prior pacing, musculoskeletal fatigue, thermal stress and terrain can all matter. There is no single universal “wall” distance.
Should I follow pace or heart rate?
Use both as context rather than obeying either one blindly. Heart rate can drift as heat and duration increase, while instant GPS pace can fluctuate. Practised race effort and reliable course splits remain important.
Calculate your own pace & splits
Choose a goal time and compare even pacing, a controlled faster or slower second half, and an elite race pattern scaled to your own target.
These are proportional split times adapted to your selected target. See source race.
Target split checkpoints
Even-pace reference| Section | Split | Elapsed |
|---|---|---|
| 5km | 21:20 | 21:20 |
| 10km | 21:20 | 42:40 |
| 15km | 21:20 | 1:03:59 |
| 20km | 21:20 | 1:25:19 |
| 25km | 21:20 | 1:46:39 |
| 30km | 21:20 | 2:07:59 |
| 35km | 21:20 | 2:29:18 |
| 40km | 21:20 | 2:50:38 |
| Finish · 42.195km | 9:22 | 3:00:00 |
Strategies are illustrative and always total your chosen finish time. The relative pacing of an elite athlete is not necessarily optimal for you; adjust for terrain, tactics and fitness.
Paces are calculated from the full official race distance. The race plan can be adjusted in Split Calculator.
References & further reading
Research and official race sources used in this guide. The article distinguishes observed pacing patterns from recommended strategies.
- Sha J et al. (2024). Pacing strategies in marathons: A systematic review. Heliyon. Review of 39 studies spanning marathon, half marathon and ultra-distance events.
- Pacing in long-distance running: sex and age differences in 10-km race and marathon (2021). Observational analysis of race pacing.
- World Athletics (2022): Kipchoge breaks world record in Berlin with 2:01:09. Official finish and intermediate timing.
- World Athletics / IAAF (2019): Nutrition for Athletics consensus statement. Event-duration and carbohydrate intake recommendations.
- Ely MT et al. (2007): Impact of weather on marathon-running performance. Medicine & Science in Sports & Exercise. Multi-event race and weather analysis.
Selectable elite model reference: Official or published elite race timings. The timing profile is scaled, not a promise of performance.