How many carbs per hour should I take?

Current guidelines suggest 30-60 g/hour for events up to 2.5 hours, and up to 90 g/hour for longer events when using dual-source carbohydrates (glucose + fructose). Start lower and build up in training.

What is dual-source carbohydrate?

Glucose and fructose use different intestinal transporters. Taking both allows absorption of up to 90 g/hour vs 60 g/hour for glucose alone. Most modern gels and drinks use this combination.

When should I take my first gel?

Most runners take their first gel 30-45 minutes into the race. Starting early maintains blood glucose before glycogen stores deplete significantly.

Do I need nutrition for a 10K?

Most runners do not need fuel during a 10K as muscle glycogen stores are sufficient for 60-90 minutes of hard effort. For half marathons and longer, a fuelling plan becomes important.

How much should I drink?

Aim for 400-800 ml per hour depending on temperature and sweat rate. Overdrinking can cause hyponatremia (low blood sodium), which is dangerous. Drink to thirst as a baseline.

RunCalcs

Race Nutrition Calculator — Fuelling Plan

Plan your race day fuelling with carbs, gels, hydration and a feeding schedule.

Race Distance

Distance measurement

Estimated Hours

Time in hours

Estimated Minutes

Time in minutes

Body Weight

Weight measurement

Intensity

Enter the intensity

How We Calculate This

Race Nutrition Planning

During prolonged exercise, the body can oxidise 60 g of carbohydrate per hour from a single source, or up to 90 g/hour using dual-source (glucose + fructose) products.

Total Carbs = Carb Rate (g/hr) x Race Duration (hrs)

The feeding schedule spaces gels evenly through the race, with the first gel taken within the first 45 minutes. Hydration is calculated from estimated sweat rate.

Frequently Asked Questions

Related Calculators

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Hydration Calculator

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Carb Loading Calculator

Calculate carbohydrate intake for race-week carb loading.

Electrolyte Calculator

Calculate electrolyte replacement needs based on sweat rate.

Energy Gel Calculator

Calculate how many energy gels you need for your race distance.

Last updated: February 2026

All calculations are estimates. Always consult a coach or medical professional for personalised training advice.