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Daily Caffeine Limit Calculator

Public-health pages often cite about 400 mg/day for most healthy adults (FDA and EFSA habitual daily), about 3 mg/kg as an EFSA single-dose figure used here as a conservative daily sketch, and about 200 mg if pregnant (ACOG/EFSA). This calculator applies those rules of thumb to your weight. It does not know your medications, heart, or sleep.

Inputs

Units
kg

Results

Suggested daily limit
210mg

A population-style cap, not a personal prescription.

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Calculation method

The sketch takes the tighter of a body-weight number (about 3 mg/kg — EFSA’s single-dose figure, not the 400 mg habitual daily) and an adult or pregnancy ceiling. FDA cites about 400 mg/day for most healthy adults and does not republish that as a pregnancy limit; if pregnant, the ceiling is 200 mg (ACOG/EFSA), then min(ceiling, 3 mg/kg) wins. A 70 kg adult lands at 210 mg from the per-kilo sketch, so 400 mg does not bind; the same person if pregnant lands at 200 mg. These figures are public round numbers, not a blood concentration.

Exact formula

suggestedLimitMg = min(pregnant ? 200 : 400, 3 × bodyWeightKg). 3 mg/kg is EFSA’s single-dose sketch (~200 mg at 70 kg), used here as a conservative daily body-weight cap; EFSA/FDA habitual adult daily is 400 mg (~5.7 mg/kg). 400 mg remains the FDA adult figure even if pregnant; 200 mg is ACOG/EFSA pregnancy guidance, not a renamed FDA cap. Limits: Age, medications, genetics and actual beverage assays omitted; not a clinic.

Sleep is a better instrument

If you are wired at midnight, you are over your personal limit even if this number still has room. The milligram cap is a ceiling, not a target.

Frequently asked questions

Does chocolate count?

Yes, in real life. This page only outputs a milligram budget. Tea, cola and dark chocolate spend it too.

I’m under 70 kg. Why not 400?

The 3 mg/kg sketch is EFSA’s single-dose figure, used here conservatively as a daily body-weight cap, so it is often lower than the 400 mg habitual adult daily. Smaller bodies often get the tighter number. A clinician may still say otherwise.

Breastfeeding?

Not modelled. Ask a clinician; do not assume the pregnancy cap or the 400 mg cap applies.

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