Long Run Fuelling Calculator
Calculate carbohydrate and fluid intake timing during long runs based on pace, duration and conditions.
Total planned run time in minutes
Your target pace per kilometre
Your body weight in kilograms
Expected weather temperature
How We Calculate This
This calculator estimates carbohydrate and fluid needs based on your run duration, pace, body weight and weather conditions.
Carbohydrate calculation
Total carbs = Carbs/hour x (Duration - 30 mins warmup)
First fuel at 30 minutes. Gel interval calculated from hourly carb target divided by carbs per gel.
Fluid calculation
Fluid/hour = Body weight (kg) x 7 ml x Weather multiplier
Cool: 0.7x, Mild: 1.0x, Warm: 1.3x, Hot: 1.6x.
Frequently Asked Questions
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Last updated: March 2026
All calculations are estimates. Always consult a coach or medical professional for personalised training advice.