Where do these caffeine figures come from?

The European Food Safety Authority's 2015 scientific opinion on caffeine safety: up to 400 mg/day and up to 200 mg in a single dose for healthy adults are not associated with safety concerns, with adolescents and pregnant/breastfeeding women given lower, separate limits.

Why does the daily limit change with body weight?

EFSA also gives a per-kilogram guide (up to 5.7 mg/kg/day for adults, 3 mg/kg/day for adolescents) alongside the flat ceiling — this calculator shows whichever of the two is lower for your entered weight, since a very light adult's weight-scaled figure can fall below the flat 400 mg cap.

Is this medical advice or a personalized safety limit?

No — this is general population-level guidance from a published food-safety opinion, not an individual risk assessment. Caffeine sensitivity varies with genetics, medication use, heart conditions, anxiety disorders and other factors this tool doesn't account for; talk to a clinician if you have a specific health concern.

How many cups of coffee does the limit represent?

The tool estimates using roughly 95 mg of caffeine per 8 oz brewed coffee, a commonly cited average — actual caffeine content varies widely by bean, roast, brew method and cup size, so use it as a rough comparison, not an exact count.

Caffeine Intake Limit Calculator

See an informational daily and single-dose caffeine guide based on EFSA's 2015 safety opinion — 400 mg/day and 200 mg per dose for healthy adults, scaled by body weight.

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Formula: Adult daily limit = min(400 mg, 5.7 mg × body weight kg); adolescent = 3 mg × body weight kg; pregnant/breastfeeding = 200 mg flat; single dose ≤ 200 mg

Worked examples

80 kg healthy adult
At 80 kg, the body-weight-scaled figure (456 mg) exceeds EFSA's flat 400 mg/day ceiling, so the ceiling applies.
50 kg healthy adult
At a lower body weight, the 5.7 mg/kg guide (285 mg) falls below the 400 mg flat ceiling, so the weight-scaled figure applies instead.
55 kg adolescent
EFSA's adolescent guidance is a flat 3 mg/kg/day with no separate ceiling, noticeably lower than the adult limit.

What this calculator does

This tool shows an informational daily and single-dose caffeine guide based on a published food-safety opinion, scaled to your body weight and population group. Enter your body weight and choose between healthy adult, adolescent, or pregnant/breastfeeding, and it returns a suggested daily limit, a suggested single-dose limit, and a rough coffee-cup equivalent for context.

Where these figures come from

The European Food Safety Authority (EFSA) published a comprehensive scientific opinion on caffeine safety in 2015, reviewing the available evidence on caffeine intake and health outcomes across population groups. Its conclusions, still the most-cited reference of this kind, are that for healthy adults, caffeine intakes up to 400 mg/day, and up to 200 mg in a single dose, are not associated with safety concerns. EFSA also provided a body-weight-scaled guide of up to 5.7 mg/kg/day for adults, a separate 3 mg/kg/day guide for adolescents, and a flat 200 mg/day limit for pregnant or breastfeeding women — the same figures this calculator applies.

How the daily limit is chosen

For adults, the calculator compares the flat 400 mg/day ceiling against the body-weight-scaled 5.7 mg/kg/day figure and returns whichever is lower. This matters because a lighter adult's weight-scaled number can fall meaningfully below 400 mg — a 50 kg adult's weight-scaled guide works out to about 285 mg, well under the flat ceiling, while a heavier adult's weight-scaled figure exceeds 400 mg and the flat ceiling becomes the binding limit instead. Adolescents use the flat per-kilogram figure directly with no separate ceiling, which is why the adolescent limit sits noticeably lower than the adult one even at a similar body weight.

What "informational only" means here

This tool applies published population-level guidance; it is not an individual risk assessment. Caffeine sensitivity varies substantially with genetics (some people metabolize caffeine far more slowly than others), medication interactions, existing heart conditions, anxiety disorders, sleep quality, and pregnancy-specific factors this calculator doesn't account for. The figures shown are reasonable starting reference points for a healthy individual with none of those complicating factors — they are not a personalized safety determination.

The coffee-cup comparison

To make the numbers more concrete, the calculator estimates roughly how many 8 oz cups of brewed coffee your daily limit represents, using about 95 mg of caffeine per cup — a commonly cited average. Actual caffeine content varies substantially by bean type, roast, brew method, and cup size, so treat this as a rough comparison rather than a precise count; a strong espresso-based drink or a large specialty coffee can contain far more caffeine than a standard drip-brewed cup.

This tool gives general population-level guidance from a published food-safety opinion. It is not medical advice — talk with a healthcare provider about a caffeine limit appropriate for your individual health situation.

Frequently asked questions

Where do these caffeine figures come from?: The European Food Safety Authority's 2015 scientific opinion on caffeine safety: up to 400 mg/day and up to 200 mg in a single dose for healthy adults are not associated with safety concerns, with adolescents and pregnant/breastfeeding women given lower, separate limits.
Why does the daily limit change with body weight?: EFSA also gives a per-kilogram guide (up to 5.7 mg/kg/day for adults, 3 mg/kg/day for adolescents) alongside the flat ceiling — this calculator shows whichever of the two is lower for your entered weight, since a very light adult's weight-scaled figure can fall below the flat 400 mg cap.
Is this medical advice or a personalized safety limit?: No — this is general population-level guidance from a published food-safety opinion, not an individual risk assessment. Caffeine sensitivity varies with genetics, medication use, heart conditions, anxiety disorders and other factors this tool doesn't account for; talk to a clinician if you have a specific health concern.
How many cups of coffee does the limit represent?: The tool estimates using roughly 95 mg of caffeine per 8 oz brewed coffee, a commonly cited average — actual caffeine content varies widely by bean, roast, brew method and cup size, so use it as a rough comparison, not an exact count.

These calculators give general estimates from published formulas. They are not medical advice and do not account for your individual health; talk to a qualified professional before changing your diet or training.