What the Published Caffeine Limits Actually Say
The calculator adds up milligrams from a reference table of drinks and compares the total
with a limit you choose. Neither half of that is a guess: the limits come from published
regulatory advice, and the drink values are per-serving figures you can check against the
container in front of you. This section lays out both, because the limits are more
specific than the single number most people remember.
The numbers behind each limit setting
Two agencies publish the figures used here. The U.S. Food and Drug Administration gives a
daily level for most adults, and the European Food Safety Authority gives both a daily
level and a single-dose level, which is the part that decides whether one large drink is
a problem.
Published caffeine guidance, by agency and population.
| Guidance | Published figure | Applies to | Source |
| Daily intake not generally associated with negative effects | 400 mg a day | Most adults | FDA |
| Daily intake with no safety concern | 400 mg a day, about 5.7 mg per kg of body weight | Healthy adults, except pregnant women | EFSA |
| Single dose with no safety concern | 200 mg, about 3 mg per kg of body weight | Healthy adults | EFSA |
| Single dose that may affect sleep in some adults | 100 mg, about 1.4 mg per kg of body weight | Adults, particularly close to bedtime | EFSA |
| Pregnancy and breastfeeding | 200 mg a day from all sources | Pregnant and lactating women | EFSA |
| Children and adolescents | 3 mg per kg of body weight a day | Children and adolescents | EFSA |
| Energy drinks | Advised against for children and teens | Children and teens | American Academy of Pediatrics, cited by FDA |
| Caffeinated drinks | Avoid for children younger than age 2 | Young children | Dietary Guidelines for Americans, cited by FDA |
| Rapid dose associated with toxic effects | About 1,200 mg, less than half a teaspoon of pure caffeine | Any adult | FDA |
Two details in that table change how the calculator should be read. First, 400 mg a day is
a daily total, while 200 mg is a single dose. Four 100 mg servings spread across a day sit
inside both, and one 300 mg serving does not. Second, the FDA describes 400 mg as about two
to three 12-fluid-ounce cups of coffee, which is a useful cross-check on any single value
you type in: if your own arithmetic disagrees with that by a wide margin, check the serving
size before trusting the number.
The same drink, measured two ways
EFSA publishes a short guideline table of caffeine per portion, and the calculator carries
its own per-serving values for the drinks it lists. Put side by side, the gap between them
is mostly portion size rather than disagreement about the drink.
EFSA guideline amounts beside the calculator’s per-serving values.
| Drink | EFSA guideline | Calculator value | Why the gap exists |
| Espresso | 80 mg in 60 ml | 63 mg in a 30 ml shot | 60 ml is closer to a double shot than a single |
| Filter coffee | 90 mg in 200 ml | 95 mg in 240 ml | A 40 ml larger cup, almost the same dose |
| Black tea | 50 mg in 220 ml | 47 mg in 240 ml | Steep time and leaf grade move tea more than volume |
| Cola | 40 mg in 355 ml | 34 mg in 355 ml | Same can, different brand formulations |
| Energy drink | 80 mg in 250 ml | 80 mg in a 250 ml can | Agreement here; a 16 oz can of another brand carries 160 mg |
| Plain chocolate | 25 mg in 50 g | 23 mg in 28 g of dark chocolate | Cocoa percentage differs between the two references |
| Milk chocolate | 10 mg in 50 g | 6 mg in 28 g | Lower cocoa solids, so less caffeine per gram |
The FDA gives ranges rather than per-brand values, and it makes two points worth keeping.
Decaffeinated coffee is not caffeine-free: the agency puts it at 2 to 15 mg in an
8-fluid-ounce cup. Energy drinks are wide: 54 to 328 mg per 16 fluid ounces, with a few
brands running 41 to 246 mg per 12 fluid ounces. Restaurants and retailers are not required
by law to tell you how much caffeine is in what they serve, so for a coffee-shop drink the
label may not exist at all and the calculator value is an estimate by drink type.
How a day adds up
Take a plausible day from the calculator’s own table: two 8 oz drip coffees at
95 mg each is 190 mg, and one 16 oz energy drink at 160 mg takes the running total to
350 mg. That is 50 mg under the FDA daily level, and a single 200 mg dose still fits inside
the EFSA single-dose figure. Add a double espresso at 126 mg and the total is 476 mg, over
the daily level while the day’s largest single serving is still only 160 mg. The two
limits answer different questions, which is why the calculator lets you switch between
them rather than showing one verdict. If sleep is the concern, the EFSA single-dose figure
of 100 mg is the tighter bound, and it applies to the drink closest to bedtime rather than
to the day’s total.
For the other half of the pairing — what to serve with the coffee — the
coffee pairing
guide works from the same idea of matching intensity, and the
chocolate
pairing guide covers the dessert side where cocoa brings its own small dose. If sugar
rather than caffeine is what you are tracking, the
sugar
substitution converter handles the gram-for-gram swaps.
Sources:
U.S. Food and Drug Administration, “Spilling the Beans: How Much Caffeine is Too Much?”;
European Food Safety Authority, “Caffeine” (Scientific Opinion on the safety of caffeine, 2015).