Cycling Fuel Calculator
Build a practical fuelling plan for your next ride: what goes in the bottles, what needs to come from gels or chews, and when to take it.
Ride details
Use feel first. Easy is usually under ~75% CP, moderate-to-tempo is ~75-90%, hard sits near that upper edge, and race/surging covers repeated climbs or attacks.
Your current fuelling
Start from your current fuelling level. The calculator will suggest the next sensible step to test.
Conditions
Temperature mainly changes fluid, sodium priority, and pacing caution. It does not automatically mean chasing a bigger carb number.
Bottle setup
Choose concentrated if you want the bottles to cover more of the target. Choose easier to drink if sweet or heavy bottles are not tested.
70 g
carbs / hour
210 g
total carbs
600 ml
fluid / hour
500 mg
sodium / hour
Today's bottle mix
Simple sugar bottle (table sugar)
Use simple sugar for the carbohydrate type. Table sugar (sucrose) provides glucose and fructose after digestion, making it the default for normal targets.
Each 750ml bottle:
- 60g table sugar
- ~1g table salt
- Water to fill
120g
carbs from bottles
90g
still needed
Ride timeline
Sip this bottle steadily.
Start sipping early to prime your gut.
Sip this bottle steadily.
Continue steady sipping pattern.
Extra carbs from gels, chews, or food.
Check labels before the ride, not when you are already tired.
Sodium guidance
Moderate sodium priorityModerate sodium priority. Use this as a starting point. Sodium needs vary a lot between riders. For many rides, seasoning to taste is enough.
Next fuelling test
Test 80-90 g/h first. If that is comfortable in a similar ride, you are close to this target.
Coaching note: Test this before race day. The goal is the highest useful amount you can tolerate and execute, not the biggest number possible.
How to use the result
This calculator is built around execution. First it works out the ride demand, then it shows what the bottles cover, what still needs to come from gels, chews, food, or refills, and how to space that across the ride.
Do not jump straight to an extreme intake because you saw a pro do it. If you have not tested the target in training, do not use it for the first time on race day.
The best fuelling plan is not the cheapest one, the most expensive one, or the biggest carb number. It is the one you have tested, can tolerate, can carry, and can execute when the ride gets hard.
The science behind the calculator
This is a starting point, not a rule. More carbohydrate is not automatically better if you cannot tolerate it.
Carbohydrate and ride demand
Carbohydrate helps support hard and long riding, especially as duration and intensity rise. The calculator scales targets with ride demand instead of treating every ride the same.
Reference: Thomas, Erdman & Burke 2016; Jeukendrup 2014.
Intensity is a guide, not a cage
Fixed percentages are useful shorthand, but they do not perfectly describe what is happening inside every rider. That is why the calculator uses simple intensity choices, with Critical Power anchors only as a guide.
Reference: Jamnick et al. 2020; SEMIPRO coaching canon.
Heat changes execution
Heat mainly changes fluid needs, sodium priority, perceived effort, and pacing. The same power can cost more in hot conditions, so the calculator treats heat as an execution warning rather than a reason to blindly increase carbohydrate.
Reference: Wingo et al. 2005; Tyler et al. 2016; Maunder et al. 2021.
Sugar, maltodextrin, glucose and fructose
Table sugar provides glucose and fructose after digestion, so it is the default for normal targets. At 90 g/h and above, the calculator switches to a 1:0.8-style mix because high-carbohydrate fuelling depends more on glucose/fructose transport and gut tolerance.
Reference: Jeukendrup 2010; Jeukendrup 2014.
Why 100-120 g/h is not the default
Ultra-high carbohydrate intake, defined as more than 90 g/h, is gaining attention in endurance sport. But the evidence does not support treating it as the default for every athlete. Use higher targets as something to test, not something to copy blindly.
Reference: Plews, Booth, Krieger & Maunder 2026.
Sodium: test and target, or season to taste
Sodium needs vary widely. For some rides, seasoning to taste is enough. For long, hot, sweaty, or high-fluid-intake rides, sodium may need to be more targeted.
Reference: McCubbin 2023.
Disclaimer: This calculator is for general education and planning. It does not replace individual advice from a qualified sports dietitian or medical professional. If you have diabetes, kidney disease, a history of hyponatraemia, eating disorder risk, significant GI issues, or medical concerns, seek individual advice.