Free tool
Caffeine dose calculator
How much caffeine actually helps — and where more just adds jitters.
The evidence range for endurance is 3–6 mg of caffeine per kg of body weight, taken 45–60 minutes out (or split for a late-race lift). More is not better — past ~6 mg/kg you mostly add jitters and gut risk.
Conservative
210 mg
3 mg/kg
Typical
315 mg
4.5 mg/kg
Max useful
420 mg
6 mg/kg
For reference, a typical caffeinated gel carries 20–40 mg, and an espresso ~65 mg. Build to your dose across the race, don't take it all at once.
Want the caffeine timed into your race plan?
Build my plan →CarbRate schedules your caffeine alongside carbs, fluid, and the course — mile by mile.
Your caffeine is only one input
Carbs, fluid, sodium, and the course all interact. CarbRate builds the whole plan and guides you through it live.