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CYCLING NUTRITION CALCULATOR

A planning estimate for carbs, fluid and sodium per hour, based on ride duration, power, session type, body weight and weather. Use training rides to personalise it.

Heat and humidity adjust the fluid and sodium starting estimates. Auto-detect from your location, type it in for a planned ride, or skip for standard conditions.

Session type and watts create a modelled estimate of carbohydrate demand. It is not a laboratory measurement of your oxidation rate.

Steady aerobic riding. Mixed fat and carb oxidation.

Your expected average power for this session. A Z2 ride at 100W needs very different fuel than Z2 at 300W.

Used to estimate fluid needs. The carbohydrate model is driven by power, session type and duration.

Choose the highest intake range you have repeatedly tolerated during exercise. This sets a planning cap, not a measured absorption limit.

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Quick answer

Enter ride duration, power, session type, body weight, gut-training level and weather. The cycling nutrition calculator returns planning estimates for carbohydrate, fluid and sodium per hour, total carbohydrate, feeding intervals and a glucose:fructose split. Rehearse the output in training and adjust it from your own tolerance and sweat-rate data.

WHAT IT DOES

A single grams-per-hour rule cannot fit a recovery spin, a hard two-hour session and a five-hour race. This tool converts the ride you are planning into a practical starting range for carbohydrate, fluid and sodium. It also shows how to divide higher carbohydrate intakes between glucose and fructose. The numbers are modelled estimates, not laboratory measurements or medical advice.

WHO IT'S FOR

  • Cyclists planning a long training ride, sportive, gran fondo or race
  • Riders comparing 30, 60, 90 or 120 g/hr carbohydrate strategies
  • Athletes practising higher intakes before an important event
  • Cyclists who want a weather-adjusted starting point before measuring sweat rate

HOW IT WORKS

The model estimates carbohydrate demand from expected power, ride duration and session type, then limits the suggested intake according to the gut-training level you select. Higher targets use glucose and fructose because they rely on different intestinal transporters. Fluid begins with body mass, intensity and weather; sodium uses a population-average sweat concentration. Those last two estimates should be replaced by your own pre/post-ride body-mass and sweat-test data when available.

  1. 01

    Describe the ride

    Enter duration, expected average power and the closest session type. These inputs drive the carbohydrate estimate.

  2. 02

    Add body weight

    Body weight is used for the fluid estimate, not to scale the carbohydrate target. Carbohydrate demand is modelled from the work being done.

  3. 03

    Set gut training honestly

    Choose beginner, moderate or trained. High targets are appropriate only after the same product and dose have been tolerated repeatedly in training.

  4. 04

    Add the conditions

    Use local or manual temperature and humidity. Weather adjusts the starting fluid estimate, but it cannot know your individual sweat rate.

  5. 05

    Rehearse and calibrate

    Spread intake across the ride, note gastrointestinal symptoms, and compare body mass before and after representative sessions. Change one variable at a time.

EXAMPLE CALCULATIONS

75kg rider, 4hr endurance ride, moderate conditions

  • · Duration: 240 min
  • · Average power: 150W
  • · Session: endurance
  • · Weight: 75kg
  • · Gut: moderate
  • · Weather: 20°C, 50% humidity

About 74 g carbohydrate/hr (296 g total), 450 ml fluid/hr and 500 mg sodium/hr. Because intake is above 60 g/hr, the tool suggests glucose plus fructose.

70kg trained rider, 5hr race, warm and humid

  • · Duration: 300 min
  • · Average power: 180W
  • · Session: race
  • · Weight: 70kg
  • · Gut: trained
  • · Weather: 28°C, 70% humidity

120 g carbohydrate/hr (600 g total) using a 1:0.8 glucose:fructose split, about 770 ml fluid/hr and 860 mg sodium/hr. This high target must be rehearsed; it is not a beginner recommendation.

LIMITATIONS

This is a planning model. It does not measure your respiratory exchange ratio, glycogen status, sweat rate, sweat sodium, gastrointestinal tolerance or medical history. Research supporting 120 g/hr comes from tightly controlled endurance protocols and trained participants; it is not a universal target. Fluid and sodium losses vary widely, while both underdrinking and overdrinking can be harmful. Never use the result to force fluid intake or ignore thirst, symptoms or body-mass gain.

When to see a coach

Speak to a registered sports dietitian or qualified clinician if gastrointestinal distress persists, you have diabetes or another condition affected by carbohydrate/fluid intake, you repeatedly gain body mass during long rides, or performance and health decline despite adequate training. A coach can help with execution; clinical nutrition questions need an appropriately qualified professional.

FREQUENTLY ASKED QUESTIONS

How many carbs per hour should I eat on the bike?+

Match intake to duration, intensity and tolerance. A short, easy ride may need no on-bike carbohydrate; 30-60 g/hr is a common starting range for longer or harder sessions; prolonged racing often uses 60-90 g/hr. Intakes around 90-120 g/hr are specialised strategies for trained riders using glucose plus fructose after repeated practice. They are not a minimum or a universal goal.

What is gut training in cycling?+

Gut training means repeatedly practising the food, drink, dose and timing you plan to use in competition. The aim is to improve tolerance and reduce gastrointestinal surprises. Increase intake gradually during suitable training rides; do not assume that every rider will tolerate 90-120 g/hr, and do not introduce a high dose for the first time on race day.

How much fluid should I drink per hour cycling?+

There is no safe universal ml-per-hour target. Needs vary with weather, intensity, body size, acclimation and individual sweat rate. Use the calculator as a starting estimate, then weigh yourself before and after representative rides while recording intake. Aim to avoid excessive dehydration without drinking so much that body mass increases; overdrinking can raise hyponatraemia risk.

Why do I bonk on long rides?+

Low carbohydrate availability is one common cause of a late-ride collapse, especially when intake does not match the duration and intensity. Starting too hard, heat stress, dehydration, illness, inadequate training and gastrointestinal problems can produce similar symptoms. Review pacing, conditions and nutrition together instead of treating every poor ride as a fuelling failure.

What is the dual-transporter model?+

Glucose and fructose use different intestinal transport pathways, so combining them can raise exogenous carbohydrate delivery compared with glucose alone during prolonged exercise. The older practical mix was often 2:1 glucose:fructose; many newer high-intake protocols use roughly 1:0.8. Neither ratio guarantees tolerance, and higher intake should be tested progressively.