Back to Home

    Caffeine Dose & Timing Calculator

    Caffeine is one of the most evidence-backed legal performance aids. Get a body-weight-based dose and the right time to take it before your race.

    Your details

    Dose scales with body weight at 3–6 mg/kg.

    Add a late top-up for 70.3/Ironman

    Unlock your personalised fuelling plan + Hexis carb targets

    Enter your email for a personalised race-day fuelling plan, plus your carb targets from our nutrition partner Hexis.

    Free Tools
    Weekly Tips
    No Spam

    Unsubscribe anytime. We respect your privacy.

    We earn a commission if you buy through this link, at no cost to you. Learn more

    Last updated: June 2026Reviewed by: Bryan Collins, founder

    How this calculator works

    Dose is calculated as 3–6 mg of caffeine per kg of body weight (the established ergogenic range), with timing set to roughly 50 minutes before the start. An optional 1 mg/kg late top-up is offered for long races.

    Assumptions

    • • Standard 3–6 mg/kg ergogenic dose
    • • Caffeine taken ~45–60 min pre-exercise

    Limitations

    • • Individual response and tolerance vary widely
    • • Product caffeine content varies — check the label

    Who this is for

    • • Triathletes and endurance athletes planning race-day caffeine
    • • Athletes rehearsing a caffeine strategy in training

    Who this is not for

    • • Anyone with caffeine sensitivity, pregnancy, or a cardiac condition
    • • Under-18 athletes

    References

    Caffeine Dose Calculator FAQ