Race Pace Planner
Enter a target time to generate kilometer splits and strategy guidance
Marathon (42.195 km)
Even pace (steady)
Target Time
03:30:00
Average Pace
4:59 / km
Average Speed
12.06 km/h
Per-kilometer pace and cumulative time
| Mileage | Split Pace | Cumulative Time | Section |
|---|---|---|---|
| 1 km | 4:59 | 00:04:59 | Start |
| 2 km | 4:59 | 00:09:57 | |
| 3 km | 4:59 | 00:14:56 | |
| 4 km | 4:59 | 00:19:54 | |
| 5 km | 4:59 | 00:24:53 | |
| 6 km | 4:59 | 00:29:52 | |
| 7 km | 4:59 | 00:34:50 | |
| 8 km | 4:59 | 00:39:49 | |
| 9 km | 4:59 | 00:44:48 | |
| 10 km | 4:59 | 00:49:46 | |
| 11 km | 4:59 | 00:54:45 | |
| 12 km | 4:59 | 00:59:43 | |
| 13 km | 4:59 | 01:04:42 | |
| 14 km | 4:59 | 01:09:41 | |
| 15 km | 4:59 | 01:14:39 | Middle |
| 16 km | 4:59 | 01:19:38 | |
| 17 km | 4:59 | 01:24:36 | |
| 18 km | 4:59 | 01:29:35 | |
| 19 km | 4:59 | 01:34:34 | |
| 20 km | 4:59 | 01:39:32 | |
| 21 km | 4:59 | 01:44:31 | |
| 22 km | 4:59 | 01:49:29 | |
| 23 km | 4:59 | 01:54:28 | |
| 24 km | 4:59 | 01:59:27 | |
| 25 km | 4:59 | 02:04:25 | |
| 26 km | 4:59 | 02:09:24 | |
| 27 km | 4:59 | 02:14:23 | |
| 28 km | 4:59 | 02:19:21 | |
| 29 km | 4:59 | 02:24:20 | Speed Up |
| 30 km | 4:59 | 02:29:18 | |
| 31 km | 4:59 | 02:34:17 | |
| 32 km | 4:59 | 02:39:16 | |
| 33 km | 4:59 | 02:44:14 | |
| 34 km | 4:59 | 02:49:13 | |
| 35 km | 4:59 | 02:54:11 | |
| 36 km | 4:59 | 02:59:10 | |
| 37 km | 4:59 | 03:04:09 | |
| 38 km | 4:59 | 03:09:07 | |
| 39 km | 4:59 | 03:14:06 | |
| 40 km | 4:59 | 03:19:05 | |
| 41 km | 4:59 | 03:24:03 | |
| 42 km | 4:59 | 03:29:02 | |
| 42.20 km | 4:59 | 03:30:00 | Finish |
Strategy Advice
- A steady pace is the safest marathon strategy: better 2 seconds slow than 2 seconds fast.
- Force the first 5 km to feel a little restrained because race-day adrenaline makes you drift too fast.
- Fuel points: drink every 5 km and take electrolytes/carbs every 10 km; halve the interval in hot weather.
- Climbs: protect breathing rather than pace, then recover time on flatter ground.
- The wall around 30 km: keep pace steady, shorten stride slightly, and focus on breathing.
This target is roughly VDOT ≈ 44.6
Want the training paces for your current VDOT? Go to VDOT Training Paces.
Even vs Negative Split: what do elite runners do?
Evidence from Boston, Berlin, Chicago, London, and other major marathons
Negative Split Data
Most men’s marathon world records from the last two decades used a negative split: Kipchoge 2:01:39 (Berlin 2018) and Kiptum 2:00:35 (Chicago 2023) both accelerated in the second half.
Positive Split Risk
Recreational runners often start too fast, slow 5-10% in the second half, and finish 10-15 minutes slower than their true ability. March et al. (2011) analyzed 186 marathons and found that a slightly slower first half was associated with better outcomes.
Even Split Is Conservative
Díaz et al. (2018, JSCR) studied non-elite PR runners: finish times were best when pace variation stayed under 3%; runners with variation above 5% averaged 5.5% more time.
Race-day suggestion: run the first 10K deliberately 5-10 sec/km slower, hold target pace through the middle, then accelerate 5-15 sec/km in the final 10K only if you have enough left. The point is not to jog the first half; it is to avoid mistaking adrenaline-driven speed for easy running.
Sources: March et al. 2011 (PubMed), Díaz et al. 2018 JSCR, World Athletics
The wall: the glycogen depletion curve
- Glycogen stores are roughly 2000 kcal (350-500 g), while a marathon can burn 2500-3000 kcal; the difference comes from fat oxidation.
- The key divide is 30-32 km: Rapoport (2010, PLoS Comput Biol) modeled glycogen depletion and showed that running above about 85% of lactate threshold can exhaust glycogen around this point.
- Why the first half cannot be too fast: running 5% faster than target pace can raise glycogen use by about 15%.
- Prevention: carb load 36-48 hours pre-race at 10-12 g/kg body weight, then take 60-90 g carbs per hour during the race.
- Fat adaptation: periodic fasted easy long runs can improve fat oxidation and spare glycogen.
Sources: Rapoport 2010 PLoS CB, Burke 2011 carb loading
Do These Before Race Day