Cycling Nutrition Calculator
Estimates the carbohydrates and fluid you need for a ride based on duration, intensity, body weight, and temperature. Use it before long rides to plan your fueling strategy and avoid bonking.
Last updated: May 2026
About this calculator
Carbohydrate needs on the bike scale with how long and how hard you ride. Sports-nutrition consensus recommends roughly 30–60 g of carbohydrate per hour for moderate efforts and up to 90 g/h for long, very hard rides — which is exactly the ladder the intensity selector encodes (Easy 30 g/h, Moderate 45 g/h, Hard 60 g/h, Very Hard 75 g/h). The formula is: carbs (g) = duration (h) × intensity (g/h) × temperature factor. Heat raises glycogen use and fluid turnover, so the temperature factor scales needs up by 20% in moderate warmth and 50% in hot conditions. Rides of an hour or less return 0 — stored glycogen comfortably covers short sessions, so in-ride fueling is unnecessary. Spread intake evenly (a gel or banana every 20–30 minutes) rather than eating it all at once, and pair carbohydrate with regular drinking.
How to use
Suppose you plan a 3-hour ride (duration = 3) at hard intensity (intensity = 60 g/h) in 20 °C weather (temperature = 1.2). Because the ride is longer than 1 hour: carbs = 3 × 60 × 1.2 = 216 g. Spread over the ride that is roughly 72 g per hour — within the recommended 30–90 g/h fueling window. The same ride in hot conditions (temperature = 1.5) needs 3 × 60 × 1.5 = 270 g, while an easy 2-hour spin in cool weather (intensity = 30, temperature = 1.0) needs just 2 × 30 × 1.0 = 60 g. A 45-minute session returns 0 — no in-ride fueling required.
Frequently asked questions
How much carbohydrate should I eat per hour when cycling for more than 2 hours?
For rides lasting more than two hours, most sports nutrition guidelines suggest consuming 60–90 g of carbohydrates per hour, depending on intensity and individual tolerance. The calculator's intensity and body-weight inputs help personalise this figure beyond a generic recommendation. Training your gut to absorb higher carbohydrate rates is also important for endurance events. Start at the lower end and increase gradually across your training rides.
Why does temperature affect hydration needs so much during cycling?
Sweat rate increases significantly in warm weather because the body uses evaporative cooling to regulate core temperature. Even a modest rise above 25 °C can double fluid losses compared with cool conditions. Failing to compensate leads to dehydration, which impairs both performance and cognitive function. The calculator adds an extra 100 ml per hour for each hour ridden above 25 °C to account for this additional loss.
What does ride intensity mean in the context of a cycling nutrition calculator?
Ride intensity is a numeric representation of how hard you are working, often aligned with a 1–10 perceived exertion scale or a power-to-threshold ratio. Higher intensity riding burns more glycogen per minute, requiring more frequent or larger carbohydrate top-ups to sustain performance. At low intensities the body relies more heavily on fat oxidation, reducing the urgency of carbohydrate intake. Matching your intensity score to your actual effort level is critical for the calculator to produce a useful estimate.