Use this carbs per hour calculator to build a practical fueling target for long runs, marathons, ultras, triathlons, and other endurance events. Enter your planned duration, fueling experience, and the carbs in your chosen fuel to get a carb-per-hour target, total event carbs, servings, and a simple 20-minute plan.
Build your plan before race day, then practice it in training. This calculator uses a progressive range: lower intake for shorter or less-practiced efforts, and higher intake only for longer events when your gut is trained for it.
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For endurance exercise lasting more than an hour, a practical starting range is 30–60 grams of carbohydrate per hour. As duration rises past roughly 2.5–3 hours, well-trained athletes can build toward 60–90 grams per hour—provided they have practiced that intake and use carbohydrate sources they tolerate.
Your body weight is not the main input for this calculator. During-event carbohydrate targets are generally planned by exercise duration, intensity, race demands, and gut tolerance. The target that matters is the one you can absorb and repeat while still running well.
| Planned duration | Practical carbohydrate range | How to use it |
|---|---|---|
| Under 60 minutes | 0–30 g/hour | Usually optional; conditions and intensity can change the need. |
| 1–2.5 hours | 30–60 g/hour | Build a simple, repeatable fueling rhythm. |
| 2.5–3 hours | 45–60 g/hour | Practice the plan at race pace before event day. |
| Over 3 hours | 60–90 g/hour | Progress gradually; higher targets require gut training. |
Small, steady doses are easier to manage than waiting until you feel depleted. Splitting your hourly target into three checks gives you a simple cue: take about one-third of your hourly carbs every 20 minutes. You can use gels, chews, drink mix, bananas, rice-based foods, or other products that fit your stomach and race logistics.
90 grams per hour is not a beginner target. It is most relevant for trained athletes in long events who have deliberately practiced a high-carb strategy. At higher intakes, sources that combine glucose or maltodextrin with fructose are often used because they use different intestinal transport pathways. Start lower, test in training, and only move up if performance and gut comfort support it.
Convenience matters when you are running for hours. Choose fuel you can tolerate and carry, then practice it. Browse Tiger Fitness sports bars and snacks for portable training fuel, and use the water intake calculator to build the rest of your daily hydration routine.
Most marathoners can start with 30–60 grams per hour, then adjust for pace, expected finish time, and what they have practiced in training. Faster or longer efforts may require the upper end of that range.
For ultras and other events lasting more than 3 hours, 60–90 grams per hour is a common performance range for athletes who have trained their gut. Start with the lowest intake you can execute consistently and build from there.
Yes. The plan works with any food or drink you tolerate. Enter the carbohydrates in one serving, then use the calculator to translate your target into total portions and timing.
Long events can blunt appetite, which is why a time-based plan is useful. Still, change course if you have nausea, severe GI symptoms, or other concerns, and seek individualized guidance when needed.
Fuel your long efforts before the tank runs low. Use this carbs per hour calculator to choose a realistic target, practice the timing, and make your race-day plan automatic.
Evidence reference: Jeukendrup, 2013; Gatorade Sports Science Institute, 2022.
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