How the intake ratio is calculated
Each group has a daily upper limit set by health authorities. This tool simply compares what you've had today against that ceiling.
- intake — today's total caffeine intake (mg)
- limit — daily limit for your group (mg)
More detail
Where the limits come from
400 mg/day for healthy adults is the ceiling cited by the U.S. FDA ("Spilling the Beans: How Much Caffeine is Too Much?", 2018). 200 mg/day for pregnancy follows ACOG Committee Opinion No. 462 (2010, reaffirmed). 100 mg/day for teens follows the American Academy of Pediatrics' recommendation for adolescents — roughly one 8 oz cup of coffee. (Health Canada instead caps adolescents at 2.5 mg/kg of body weight per day.)
Counting your actual intake
An 8 oz brewed coffee has about 95 mg, a shot of espresso about 63 mg, a 12 oz cola about 30–40 mg, and a typical energy drink 80–150 mg per can. Add up everything you've had today, including tea and chocolate, before entering the total.
Practical tip. Caffeine has a half-life of roughly 5 hours, so a large dose late in the day can still leave you at 25% of it in your system 10 hours later — intake amount and timing both matter for sleep.
Frequently asked questions
What is the daily caffeine limit for adults?
400 mg/day for healthy adults, per the U.S. FDA (2018) — roughly four 8 oz cups of brewed coffee. Enter your total intake above to see it as a percentage of this limit.
How much caffeine is safe during pregnancy?
ACOG recommends staying under 200 mg/day during pregnancy (Committee Opinion No. 462), about half the general adult limit. Select "Pregnant" above to check today's intake against this lower ceiling.
What's the caffeine limit for teenagers?
The American Academy of Pediatrics recommends adolescents consume no more than 100 mg/day — about one 8 oz cup of coffee — well below the adult limit because of teens' smaller body size and developing systems.
How is the intake percentage calculated?
pct = intake ÷ limit × 100, where limit depends on your selected group (400/200/100 mg). 100% or higher means today's total has reached or passed the recommended ceiling for that group.
Does going over the limit occasionally cause harm?
These are general guidelines, not hard medical thresholds — occasional excess isn't automatically dangerous for most healthy adults, but individual sensitivity varies. If you're pregnant, have a heart condition, or exceed the limit regularly, consult a doctor.