The number of gels on race day should be calculated based on your expected finish time, your carbohydrate target per hour and what your stomach can handle.
- Many endurance athletes use 1 gel every 30 to 45 minutes as a rule of thumb for longer races.
- A gel typically contains around 25 g of carbohydrate, but the nutrition label on the specific variant should always be checked.
- Carbohydrate from sports drink, chews and aid stations must be included in your overall plan.
- The plan should be tested in training, so timing, taste, caffeine and stomach comfort work on race day.
Race day is not only about your legs. It is also about having an energy intake plan that matches your distance, your pace and your stomach.
When your heart rate rises and your body is working at high intensity, it can be an advantage to have planned your carbohydrate intake from the start. Not as an emergency solution, but as part of your strategy all the way to the finish line.
The short answer
A practical starting point is to work backwards from your expected finish time and your target for carbohydrate per hour. Only then does it make sense to decide how many gels you want to carry in your pocket, belt or tri suit.
A common rule of thumb is that many endurance athletes use 1 gel every 30 to 45 minutes in longer races. For many, this equals around 1 to 2 gels per hour, depending on how much carbohydrate is in the gel you use and whether you also get carbohydrate from sports drink, chews or aid stations along the way.
PurePower Energy Gels typically contain around 25 g of carbohydrate per gel, but always check the nutrition label on the specific variant. If you need to stock up for your race, you can see the selection of Energy Gels for race day and choose the flavours you have already tested in training.
Use this simple formula:
Expected finish time in hours × number of gels per hour = total number of gels
If you run a marathon in 4 hours and plan 2 gels per hour, you will need around 8 gels. It can be practical to bring 1 extra as backup if the race takes longer than planned or you miss an aid station.
Carbohydrate per hour determines your gel plan
The most important question is not only: “How many gels should I take?”
It is: “How many grams of carbohydrate do I want to hit per hour?”
As a practical starting point, many endurance athletes use these ranges:
Practical ranges for carbohydrate per hour
- 0 to 30 g carbohydrate per hour for shorter or less demanding races.
- 30 to 60 g carbohydrate per hour for longer races such as half marathon and marathon.
- 60 to 90 g carbohydrate per hour for longer and harder endurance events, if your stomach is trained for it.
The body’s use of carbohydrate depends, among other things, on intensity, training level, carbohydrate sources and individual stomach tolerance. If you want to go deeper into the numbers, you can read PurePower’s guide to how much carbohydrate the body can absorb per hour.
If one gel provides around 25 g of carbohydrate, 50 g of carbohydrate per hour equals around 2 gels per hour. If you also get carbohydrate from sports drink, chews or aid stations, it must be included in the overall plan.
Examples of gels for 10K, half marathon and marathon
Here are practical examples based on gels with around 25 g of carbohydrate. Use them as a starting point, not as the definitive answer. Your plan should be adapted to your body, your pace and your stomach.
| Distance or event | Typical duration | Possible gel need |
|---|---|---|
| 10K | 40 to 70 min | 0 to 1 gel |
| Half marathon | 1:30 to 2:30 | 2 to 4 gels |
| Marathon | 3:00 to 5:00 | 4 to 8 gels |
| Long cycling race | 3 to 6 hours | 6 to 12 gels, if gels are the main source |
| Triathlon or middle distance | 3 to 6+ hours | Depends on bike drink, run leg and aid stations |
For 10K, gels are not necessary for many people if they have eaten appropriately before the start. However, some choose one gel 10 to 15 minutes before the start, especially if the race is hard or if breakfast was a long time ago.
For half marathon, 2 to 3 gels can be a practical starting point for many: one after 30 to 40 minutes, one around 60 to 75 minutes and possibly one extra towards the end.
For marathon, the plan often becomes more important. Here, 1 gel every 30 minutes can be a simple model, but it should be tested on long training runs. Race day is not the day to experiment.
If you are still trying out flavours and variants with or without caffeine, an Energy Gels mix pack can be practical during the training period.
Timing your first gel
A common mistake is waiting until your energy level feels low. On race day, gels can be used as part of the plan and not only as a solution when you feel under pressure.
A simple timing plan can look like this:
- Possibly 1 gel 10 to 15 minutes before the start, if you have tested it.
- First gel after 25 to 40 minutes of running.
- Then one gel approximately every 30 to 45 minutes.
- Ideally take gels around aid stations, so you can rinse them down with water.
Many people find that gels work best with a little water. Avoid washing a gel down with very sweet sports drink if you are already high in carbohydrate per hour. For some, this can create a heavy feeling in the stomach.
Gels together with drinks and chews
Gels are easy to dose. They take up little space and are developed for situations involving speed, competition and long sessions where you want simple carbohydrate intake along the way.
But they do not have to stand alone. In longer races, it can make sense to combine several carbohydrate sources, so you get variation and can plan both energy and fluids.
For example, you can use:
- Gels for simple dosing during running.
- Sports drink on the bike or at your own aid stations.
- Chews if you want to spread your carbohydrate intake into smaller bites.
- Electrolytes in heat, with a high sweat rate or during long events.
If you do not like taking a whole gel at once, Energy Chews as an alternative to gels can be a flexible solution. They make it possible to take smaller amounts continuously rather than larger portions all at once.
For cycling races, triathlon or long training sessions, energy powder for longer races can also be used as a base in your bottle, while gels are used as a supplement. Remember that carbohydrate from your drink counts in the overall total.
Stomach comfort before race day
An energy plan should not only look good on paper. It also needs to work when your heart rate is high, your breathing is hard and your body is working.
Stomach tolerance is individual. It can also be adapted gradually, just like pace and endurance.
Typical mistakes are:
- Taking the first gel too late.
- Taking several gels close together.
- Using new flavours or caffeine variants on race day.
- Forgetting water with gels.
- Combining many gels with strong sports drink without calculating the total.
Caffeinated gels can be relevant for some, but they should be used with care. Some people are sensitive to caffeine and may experience restlessness, a feeling of high heart rate or stomach discomfort. Therefore, test both dose and timing in training.
Fluids are also part of the plan. On hot days or with a high sweat rate, electrolytes for race day may be relevant as part of your overall strategy for fluids and salts.
Your practical race day checklist
Before you pack your race bib, shoes and gels, make a concrete plan.
Race day checklist
- Write down your expected finish time.
- Choose your target for carbohydrate per hour.
- Check how much carbohydrate is in your gels.
- Decide fixed times for intake.
- Plan water for each gel.
- Include energy from sports drink and aid stations.
- Bring 1 to 2 extra gels for long events.
The right number of gels is not the same for everyone. For some, 2 gels are enough for a half marathon. For others, a marathon may require 8 or more, depending on duration and the overall carbohydrate plan.
The key is that your plan matches your duration, your carbohydrate target and your stomach. Test it in training, adjust it and use it as a calm framework on the day.
That gives you a more planned starting point for your carbohydrate intake when the starting gun goes off and the work begins all the way to the finish line.