The marathon punishes one mistake above all others: going out too fast. Those early kilometres feel effortless, the crowd is loud, and your taper has you fresh — so you bank a few seconds per kilometre. Then somewhere after 30K, the bill comes due. Here's how to avoid it.
Pick a realistic goal first
Pacing strategy is meaningless without an honest goal. Base it on your recent training and a recent shorter race, not on hope. Our race time predictor will estimate a marathon range from a recent 10K or half — note that it's a range, and that predicting a marathon from a short race assumes you've actually done the long-run training.
Even or slightly negative splits
The fastest marathons are run on even or slightly negative splits — the second half as fast as, or faster than, the first. Practically, that means starting 5–10 seconds per kilometre slower than goal pace for the first few kilometres, settling into goal pace, and only pushing in the final 10K if you have it.
Use the race pace calculator to build a split sheet. If your goal is 4:00:00, that's about 5:41/km — so you want to pass halfway around 1:59–2:00, not 1:55.
Fuel before you're empty
Your body stores roughly 90 minutes of glycogen at marathon effort. Start taking carbohydrate early — around 30–60g per hour — from the first 30–40 minutes, not when you feel low. By the time you feel empty, it's too late to fully recover.
Effort, not pace, on a tough day
Heat, wind, and hills all raise the effort of any given pace. On a hot day, adjust your goal before the start and run by effort. A marathon run 10 seconds per kilometre too fast in the heat will cost you minutes later.
Train the way you'll race
Race-pace long runs are the most specific marathon workout there is. A good marathon plan rehearses goal pace and fueling in training, so race day is a repeat of something you've already done — not a gamble.
Run the first half with your head and the second half with your legs. Build your plan and practise the pacing long before race morning.