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Fueling calculator

How much to eat and drink per hour for your race, and what that looks like in bottles and gels. Based on widely used sports-nutrition ranges.

Intensity
Conditions
How much do you sweat?
Have you practised high-carb fueling in training?

Your fueling plan, per hour

Carbs

60 g

Fluid

500 ml

Sodium

400 mg

In practice, each hour

1.0 bottle of drink mix + 2 gels

Based on a 500 ml bottle with about 30 g of carbs and gels of about 25 g.

For the whole 4:30 h

250 g carbs and 2.3 l of fluid

Every 20 minutes

  1. 0:2020 g, 167 ml
  2. 0:4020 g, 167 ml
  3. 1:0020 g, 167 ml
  4. 1:2020 g, 167 ml
  5. 1:4020 g, 167 ml
  6. 2:0020 g, 167 ml
  7. 2:2020 g, 167 ml
  8. 2:4020 g, 167 ml
  9. 3:0020 g, 167 ml
  10. 3:2020 g, 167 ml
  11. 3:4020 g, 167 ml
  12. 4:0020 g, 167 ml
  13. 4:2020 g, 167 ml

General guidance from widely used sports-nutrition ranges, not medical advice. Practise your race fueling in training first. With a medical condition, ask a professional.

The numbers behind the plan

DurationCarbs per hour
Under 1 hourNot needed; a mouth rinse can help in a hard effort
1 to 2.5 hours30 to 60 g
Over 2.5 hours60 g, up to 90 g when your gut is trained

These ranges follow the joint position stand on nutrition and athletic performance from the American College of Sports Medicine, the Academy of Nutrition and Dietetics and Dietitians of Canada (2016), and Asker Jeukendrup’s work on carbohydrate intake during exercise (Sports Medicine, 2014). Fluid and sodium start from common ranges and move with heat and how much you sweat.

Train your race fueling

  • Practise your exact race products on long training rides and runs.
  • Build up carbs per hour over a few weeks, not on race day.
  • Set a timer: every 20 minutes is easier to follow than “when I feel like it”.
  • In a triathlon, most of your fueling happens on the bike, where it’s easiest to eat.

For a full walk-through, read our race-day fueling guide.

Questions

How many carbs per hour do I need?

For efforts of 1 to 2.5 hours, 30 to 60 g per hour is a common range. For longer efforts, up to 90 g per hour can help, but only if you've practised it, because your gut needs training to absorb that much.

Why does it ask whether I've practised high-carb fueling?

High carb intakes during exercise are well tolerated by athletes who train their gut for it, and can cause stomach trouble in those who haven't. The calculator stays at 60 g per hour until you say you've practised.

How much should I drink?

Most athletes land between 400 and 800 ml per hour, more in the heat and for heavy sweaters. Drinking to thirst is a sensible guide; don't drink so much that you gain weight during a race.

Do I need salt?

In long or hot races, replacing some sodium helps many athletes, especially heavy or salty sweaters. Sports drinks and electrolyte products make it easy.

Is this medical advice?

No. It's general guidance for healthy adults. If you have a medical condition, such as diabetes or a heart, kidney or blood pressure condition, ask a professional before changing how you fuel.

Your finish starts here.

One race. One complete plan. An app that brings your training, fueling practice and race-day preparation together around the race you’re training for.

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