Free tool

Caffeine Calculator

Calculate the optimal ergogenic caffeine dose for your clients based on body weight and training goal. Based on the recommendations of the ISSN (International Society of Sports Nutrition).

Why calculate your caffeine dose?

Caffeine is the most studied and effective ergogenic supplement. The optimal dose depends on body weight: 3-6 mg/kg improves performance in strength, endurance and power according to the ISSN.

The safe daily caffeine limit for healthy adults is 400 mg (FDA/EFSA). People sensitive to caffeine should use lower doses.

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How much caffeine should an athlete take?

The optimal caffeine dose for athletes is determined by body weight, not a fixed number. Research consistently shows that 3-6 mg per kilogram of body weight is the ergogenic sweet spot: enough to meaningfully improve performance without pushing into the range where side effects outweigh benefits.

Body weightLow dose (3 mg/kg)High dose (6 mg/kg)
60 kg (132 lb)180 mg360 mg
70 kg (154 lb)210 mg420 mg*
80 kg (176 lb)240 mg480 mg*
90 kg (198 lb)270 mg540 mg*

* Exceeds the FDA/EFSA safe daily limit of 400 mg. Use the minimum of the range or cap at 400 mg.

Caffeine timing: when to take it for best results

Timing caffeine correctly is as important as the dose itself. Caffeine peaks in the bloodstream 30-90 minutes after ingestion, so the standard recommendation is to consume it 45-60 minutes before training. For morning sessions this is straightforward; for evening workouts, keep in mind that caffeine has a half-life of 4-6 hours and can disrupt sleep if taken too late.

Coaches can use this calculator to give clients a personalised mg target rather than relying on generic product serving sizes, which are often too high for lighter athletes or too low for heavier ones.

Frequently asked questions