Gradescale

Carb-Per-Hour Fueling Calculator

Per-hour carbohydrate intake targets for endurance races, using the Jeukendrup (2014) multi-transporter framework

Inputs

Planned ride or race duration

50% (easy)85% (tempo)120% (race)

Ambient temperature affects GI risk and drink concentration

Results

Total carbs/hr79g/hr
Glucose/hr53g/hr
Fructose/hr26g/hr
Ratio2:1 Glucose:Fructose
Total carbs237g
Total energy948kcal

Practical delivery

Gels (25 g each)3.2/hr
Bottles (500 ml, ~8%)1.8/hr
Drink concentration9g/100mL
GI Risk:Low (2/5)

Cumulative carb intake

Hr 1Hr 2Hr 30g60g120g180g240g

Drink concentration capped at 90 g/L due to conditions. Use gels for remaining carbs.

Get the full picture

These calculators are a slice of what Gradescale does. Sign up free to track training load, fitness trends, and race readiness across every workout — no credit card required.