Even pace or negative split?
Even pacing is the simplest plan and close to optimal on a flat course. A small negative split — starting a little slower than goal pace and finishing faster — protects you from the classic mistake of burning glycogen in the first 10 km on adrenaline. This calculator keeps a constant pace within each half and makes the second half the chosen percentage faster, so the total still matches your goal time.
Marathon split cheat sheet
| Goal | Half-way (even) | Pace /km | Pace /mile |
|---|---|---|---|
| 3:00:00 | 1:30:00 | 4:16 | 6:52 |
| 3:30:00 | 1:45:00 | 4:59 | 8:01 |
| 4:00:00 | 2:00:00 | 5:41 | 9:09 |
| 4:30:00 | 2:15:00 | 6:24 | 10:18 |
| 5:00:00 | 2:30:00 | 7:07 | 11:27 |
Need a goal time first? Try the race time predictor.
Frequently asked questions
What is a negative split?
Running the second half of a race faster than the first. Most marathon world records were run with even or slightly negative splits, because starting too fast costs far more time later than it saves early.
How much faster should the second half be?
For most runners 1–2% is plenty: on a 4-hour marathon that is a first half of about 2:01 and a second half of about 1:59. Larger negative splits only make sense on courses that get easier.
Why does my watch show a longer distance than the race?
Races are measured along the shortest possible line. Weaving around other runners and GPS error typically add 0.5–1%, so plan to run each kilometre a couple of seconds faster than the split table suggests.
How do I make a pace band?
Choose the distance, goal time and split strategy, switch to “Every 5 km” or “Every mile” if you want a compact band, and press Print. Only the split table is printed.