The right number of energy gels depends more on your expected finish time than the race distance alone. A fast half marathon and a four-hour marathon have very different fuelling demands, and sports drinks, chews and food all count toward your total carbohydrate intake.
This practical guide shows how to estimate your needs for a 10K, half marathon or marathon without assuming that every runner—or every gel—is the same.
Start with time, not distance
The Australian Institute of Sport (AIS) provides general carbohydrate targets based on exercise duration:
- Less than 45 minutes: additional carbohydrate is generally not needed.
- Approximately 45–75 minutes: small amounts of carbohydrate may help during sustained high-intensity exercise.
- Approximately 1–2.5 hours: around 30–60 g of carbohydrate per hour.
- Longer than 2.5–3 hours: up to 90 g per hour may be useful for trained athletes using an appropriate mixture of carbohydrates.
These are general sports-nutrition guidelines, not a requirement to consume the maximum amount. Your pre-race meal, pace, gut tolerance and other fuel sources all matter.
How to calculate the number of gels
First, check the nutrition label for carbohydrate per sachet. Then use this calculation:
Expected race hours × carbohydrate target per hour ÷ carbohydrate per gel
For example, a runner expecting to finish in two hours and starting with a target of 30 g per hour needs about 60 g of carbohydrate during the race. If one gel provides 25 g, that works out to approximately three gels. If the runner also drinks a sports drink containing carbohydrate, fewer gels may be required.
Round the result into a practical plan, then test it during training. Do not copy another runner’s gel count without checking their pace, product and other fuel sources.
How many gels for a 10K?
Many runners finish a 10K within 45–75 minutes. In this range, a full gel may not be necessary when you have eaten appropriately before the event. Small amounts of carbohydrate may still be useful during sustained high-intensity efforts, but this does not automatically mean every runner needs a gel.
If your 10K is expected to take longer than about 75 minutes, calculate your plan using the 30–60 g-per-hour range and begin conservatively. Practise before race day to confirm that the timing and texture feel comfortable.
How many gels for a half marathon?
A half marathon often lasts between one and 2.5 hours, placing many runners in the AIS range of 30–60 g of carbohydrate per hour. The exact number of gels depends on the carbohydrate in each sachet and whether you also use sports drinks, chews or food.
A runner close to 75–90 minutes may choose a lower intake than someone running for more than two hours. Calculate the total, spread it across the race and avoid taking several gels together.
How many gels for a marathon?
For a marathon lasting longer than 2.5–3 hours, carbohydrate becomes increasingly important. AIS guidance allows for intakes up to 90 g per hour, but higher rates are not a suitable starting point for everyone. They generally require products containing multiple transportable carbohydrates and repeated gut training.
Start with an intake that you have tolerated during long runs. Count carbohydrate from every source, including aid-station drinks. Carry a small backup only if you know you can tolerate it and can transport it safely.
When should you take each gel?
There is no universal kilometre marker that suits every runner. Spread your planned intake across the expected duration instead of waiting until you feel completely depleted. Your schedule should also match water-station locations and the product directions.
The official N8 Refuel guidance recommends one packet for every hour of activity and says it may be used before, during or after activity. Treat this as the manufacturer’s direction for that product—not as a universal rule for every gel or athlete.
Remember hydration and Malaysian conditions
Fuel and hydration are related but separate. Hot and humid conditions can change your fluid needs, while drinking excessive fluid can also be unsafe. Most concentrated gels should be consumed with adequate fluid unless the product is specifically formulated otherwise.
N8 Refuel is marketed as not requiring water, but runners still need a suitable hydration plan for the weather, duration and individual sweat rate.
Test the plan before race day
- Choose a long run that resembles your expected race duration.
- Check the carbohydrate and caffeine content of every product.
- Begin with a conservative hourly target.
- Record gel timing, fluid intake and any stomach symptoms.
- Adjust gradually across several sessions.
Never introduce a new gel, caffeine dose or substantially higher carbohydrate intake for the first time during an important race.
Build your energy-gel plan
Read our guide to using energy gels, browse the energy gels and sports fuel collection, compare the N8 Refuel 10-pack, or begin with an individual N8 Refuel sachet during training.
Sources
- Australian Institute of Sport: How and when to use sports gels
- World Athletics: Nutrition strategies for distance runners and race walkers
- Official N8 Refuel product information
This article provides general educational information. Athletes with medical conditions, dietary restrictions or specific performance needs should consult a qualified healthcare professional or sports dietitian.