Mavr Sports Nutrition Team
Updated October 2, 2026. 9 min read.
Most runners need 2 to 4 gels for a half marathon: take the first one about 20 to 30 minutes in, then one every 25 to 30 minutes until about 15 minutes before the finish. Faster runners need fewer, slower runners need more.
The chart below shows how many gels and how many grams of carbs per hour fit your finish time. It assumes a standard gel with about 25 g of carbs and no sports drink. If you also drink sports drink, take fewer gels.
| Finish time | Gels (25 g each) | Carbs per hour | When to take them (minutes) |
|---|---|---|---|
| 1:15 or faster | 0 to 1 | 0 to 20 g | Optional gel at 25 to 30 |
| 1:30 | 2 to 3 | 35 to 50 g | 25, 50, 70 |
| 1:45 | 3 to 4 | 45 to 55 g | 20, 45, 70, 90 |
| 2:00 | 3 to 4 | 40 to 50 g | 20, 45, 70, 95 |
| 2:15 | 4 to 5 | 45 to 55 g | 20, 45, 70, 95, 120 |
| 2:30 | 4 to 5 | 40 to 50 g | 20, 45, 70, 95, 120 |
| 3:00 | 5 to 6 | 40 to 50 g | 20, 45, 70, 95, 120, 145 |
Take the lower number if your stomach is sensitive, you had a big breakfast, or you drink sports drink on the course. Take the higher number if you are a bigger runner, it is warm, or you have trained your gut with gels on long runs.
Sports nutrition guidelines suggest about 30 to 60 g of carbs per hour for exercise lasting 1 to 2.5 hours. Most half marathons fall right in that window. The chart keeps most runners between about 35 and 55 g per hour, which is enough to hold pace in the last 5 km without overloading the gut at race pace.
For efforts under about 75 minutes, research shows that small amounts of carbs, or even rinsing a sports drink in the mouth, give most of the benefit. That is why fast runners can skip gels or take just one.
Gels are not all the same size. A Maurten Gel 100 has 25 g of carbs and a GU Energy Gel has about 22 g. Some larger gels have more. Always check the label, then divide your target carbs per hour by the carbs in your gel to see how often to take one.
Carbs in your drink count. A typical 6% sports drink has about 6 g of carbs per 100 ml, so 500 ml gives you about 30 g, a bit more than one gel. If you drink 250 ml of sports drink at two aid stations, take one fewer gel than the chart says.
Check the race website to see which drink is on course, how strong it is, and where the aid stations are. Then try that drink in training. Do not assume you will tolerate it on race day.
1:40 runner, gels only
Gel timing20, 45, 70 min
Total carbs75 g (about 45 g per hour)
2:00 runner, gels only
Gel timing20, 45, 70, 95 min
Total carbs100 g (50 g per hour)
2:00 runner, gels + drink
Gel timingGels at 20, 55, 90 min, 250 ml drink at 40 min
Total carbsAbout 90 g (45 g per hour)
2:30 runner, gels only
Gel timing20, 45, 70, 95, 120 min
Total carbs125 g (50 g per hour)
| Plan | Gel timing | Total carbs |
|---|---|---|
| 1:40 runner, gels only | 20, 45, 70 min | 75 g (about 45 g per hour) |
| 2:00 runner, gels only | 20, 45, 70, 95 min | 100 g (50 g per hour) |
| 2:00 runner, gels + drink | Gels at 20, 55, 90 min, 250 ml drink at 40 min | About 90 g (45 g per hour) |
| 2:30 runner, gels only | 20, 45, 70, 95, 120 min | 125 g (50 g per hour) |
Gel count is only one part of the plan. These are the targets behind it:
Most runners need 2 to 4 gels: 2 to 3 for a 1:30 finish, 3 to 4 for about 2:00, and 4 to 6 for 2:30 to 3:00. Runners finishing in about 1:15 or faster may need one or none.
Not always. If you finish in about 75 minutes or less, a good breakfast and a few sips of sports drink may be enough. For most runners, who take longer than that, gels help hold pace in the last few miles.
About 20 to 30 minutes in, then every 25 to 30 minutes. Do not wait until you feel tired.
About 30 to 60 g per hour fits most half marathons. With 25 g gels, that is roughly one gel every 25 to 45 minutes.
Try smaller amounts more often, always take them with water, and practice in training. You can also get part of your carbs from sports drink instead.
Only if you have tried them in training. A caffeine gel in the second half can help some runners, but it can also upset the stomach.
General guidance for healthy adults, not medical advice. Talk to a doctor or registered dietitian if you have a health condition, take medicines or have special dietary needs. Caffeine advice is for healthy adults only. EFSA's safe limit is 200 mg in one dose and 400 mg in a day.
Use the free Mavr half marathon fuel calculator to get gel timing for your pace.
Ask Kai, the coach in the app