Carbs Per Hour by Run Duration and Intensity
Grams of carbohydrate per hour, based on standard sports nutrition guidance (30-60g/hour for 1-2.5 hour efforts, up to 90g/hour beyond that with multiple transportable carbohydrates).
| Run Duration | Easy / Recovery | Moderate / Long Run | Race Pace | Carb Source |
|---|---|---|---|---|
| Under 60 min | None needed | None needed | 0-15g (optional) | Water only; carb mouth rinse optional for races |
| 60-90 min | 0-20g/hr | 20-30g/hr | 30-45g/hr | Single source (glucose) is fine |
| 90 min - 2 hr | 20-30g/hr | 30-45g/hr | 45-60g/hr | Single source is fine up to 60g/hr |
| 2 - 2.5 hr | 30-45g/hr | 45-60g/hr | 60-75g/hr | Glucose + fructose mix recommended above 60g/hr |
| 2.5 - 3.5 hr | 40-50g/hr | 50-70g/hr | 60-90g/hr | Glucose + fructose (2:1 or 1:0.8 ratio) required |
| 3.5 hr + (ultra) | 40-60g/hr | 60-80g/hr | 80-90g/hr | Mixed sources + some solid food; trained gut only |
Key rule: Glucose absorption saturates around 60g/hour. To go higher, you must add fructose, which uses a separate intestinal transporter. That is why dual-source products list a glucose-to-fructose ratio.
Gel, Chew, and Drink Carb Equivalents
Typical carbohydrate content per serving. Always check your specific product label; formulas vary.
| Fuel Source | Carbs Per Serving | Servings for 30g/hr | Servings for 60g/hr | Servings for 90g/hr |
|---|---|---|---|---|
| Standard energy gel | 22-25g | 1-1.5 | 2.5 | 3.5-4 |
| High-carb / dual-fuel gel | 40g | 0.75 | 1.5 | 2-2.5 |
| Energy chews (full packet) | 22-24g | 1-1.5 | 2.5 | 3.5-4 |
| Sports drink, standard 6% (500 ml bottle) | 28-30g | 1 bottle | 2 bottles | 3 bottles |
| High-carb drink mix (500 ml bottle) | 80g | 0.4 bottle | 0.75 bottle | 1.1 bottles |
| Race-course drink (typical 240 ml / 8 oz cup) | 12-15g | 2 cups | 4-5 cups | 6-7 cups |
| Medium banana | 27g | 1 | 2 | 3 |
| Medjool dates (2) | 36g | 2 dates | 3-4 dates | 5 dates |
Mixing sources counts toward the same hourly total: one gel (25g) + one 500 ml bottle of standard sports drink (30g) per hour = 55g/hour.
Marathon Fueling Schedule by Finish Time
Total carbohydrate and gel count (standard 25g gels) at three hourly targets. Take the first gel 20-30 minutes in, then one every 20-25 minutes. Stop fueling with about 20 minutes to go.
| Finish Time | Total at 45g/hr | Total at 60g/hr | Total at 90g/hr | Gels at 60g/hr | Gel Timing |
|---|---|---|---|---|---|
| 2:45 | 124g | 165g | 248g | 6-7 | Every 22-25 min |
| 3:00 | 135g | 180g | 270g | 7-8 | Every 22-25 min |
| 3:15 | 146g | 195g | 293g | 8 | Every 22-25 min |
| 3:30 | 158g | 210g | 315g | 8-9 | Every 20-25 min |
| 3:45 | 169g | 225g | 338g | 9 | Every 20-25 min |
| 4:00 | 180g | 240g | 360g | 10 | Every 20-25 min |
| 4:15 | 191g | 255g | 383g | 10-11 | Every 20-25 min |
| 4:30 | 203g | 270g | 405g | 11 | Every 20 min |
| 5:00 | 225g | 300g | 450g | 12 | Every 20 min |
| 5:30 | 248g | 330g | 495g | 13 | Every 20 min |
Slower finishers run at lower intensity and can often sit at 45-60g/hour comfortably. Faster finishers burn carbohydrate at a higher rate and should prioritize the 60g/hour column or above.
Want a Personalized Fueling Plan?
Our Race Nutrition Calculator builds an hour-by-hour carb and fluid plan from your race distance, pace, and body weight.
Open Race Nutrition CalculatorHow to Use This Fueling Chart
- Estimate your duration. Use your goal finish time, not the race distance. A 4:30 marathoner needs a very different plan than a 2:45 marathoner. Our race time predictor can estimate this from a recent shorter race.
- Pick your hourly target from the first chart. Find your duration row and intensity column. When in doubt, start at the low end of the range.
- Convert to products with the second chart. Decide the mix of gels, chews, and drink that gets you to your hourly number, and note what the race serves on course.
- Rehearse on long runs. Practice the exact products, amounts, and timing at least 2-4 times before race day. Increase by 10-15g/hour every week or two if you are building toward 90g/hour.
- Start early and stay on schedule. The most common fueling error is starting too late. Carbs eaten at mile 20 cannot fix a deficit created in the first 90 minutes.
Hydration Is a Separate System
Carbohydrate targets and fluid targets are calculated independently. Most runners need 400-800 ml of fluid per hour depending on heat and sweat rate. Use our sweat test calculator to measure your personal rate, then choose whether your carbs come from the bottle, from gels, or both.
Frequently Asked Questions
How many carbs per hour should I eat during a marathon?
Standard guidance is 60-90g per hour for efforts over 2.5 hours. Runners under 3 hours can often stay near 60-75g/hour; anyone racing 3 hours or longer benefits from working toward 60-90g/hour with a glucose plus fructose mix.
How many gels do I need for a marathon?
At 60g/hour with standard 22-25g gels: about 8 gels for a 3:00 finish, 9-10 for 3:30, 10 for 4:00, 11 for 4:30, and 12 for 5:00. One gel every 20-25 minutes hits the target. On-course sports drink can replace 1-2 gels per hour.
Do I need to fuel a run under 60 minutes?
No. Stored glycogen covers runs under 60-75 minutes. Fueling starts to matter from 60-90 minutes and becomes critical beyond 2 hours.
What is the maximum carbs per hour the body can absorb?
Roughly 60g/hour from glucose alone. Adding fructose in a 2:1 or 1:0.8 glucose-to-fructose ratio raises the practical ceiling to about 90g/hour. Some trained athletes reach 100-120g/hour after deliberate gut training.
How do I train my gut to handle more carbs?
Fuel your long runs at race intake using race-day products, starting at 30-45g/hour and adding 10-15g/hour every week or two. Most runners adapt within 2-4 weeks of consistent practice.
Is 30 grams of carbs per hour enough for a long run?
For easy 60-90 minute runs, yes. For runs of 2 hours or more, treat 30g/hour as the floor; most runners perform and recover better at 45-60g/hour, and marathon-pace long runs should rehearse full race intake.
Disclaimer: This chart is a research-based reference compiled from published sports nutrition guidance. It is for informational purposes only and is not medical or dietetic advice. Individual carbohydrate tolerance varies widely, and conditions such as diabetes or GI disorders change these recommendations. Consult a physician or registered sports dietitian before making significant changes to your race nutrition.