Daily Caffeine Cutoff Curve
When does your coffee actually wear off? Add your day's drinks and your bedtime to see how much caffeine is still active at lights-out, the range your body might really be in, and your personal last call for a caffeine-quiet night.
400 mg
for healthy adults — FDA & Health Canada
~5 hours
individual range runs 2–12 hours
≈50 mg
at bedtime — from sleep-latency research
Caffeine leaves your system by halves: roughly every 5 hours, your body clears half of what's left. A 150 mg latte at 3 p.m. is still ~75 mg at 8 p.m. and ~50 mg near a typical bedtime. The curve adds every drink in your day together — and because clearance genuinely varies from person to person (about 2 to 12 hours), we draw a range, not a single confident line.
The half-life math means an afternoon coffee is, in effect, a bedtime-adjacent dose — sleep research associates meaningful caffeine at lights-out with taking longer to fall asleep and lighter sleep. Your curve computes a personal "last call": the latest a standard coffee still fades below the sleep-sensitivity guide by your bedtime.
Method & Sources
Caffeine amounts are compiled from brand nutrition pages and USDA FoodData Central (retrieved July 2026). We model caffeine clearing with first-order elimination at a ~5-hour average half-life, and because everyone clears caffeine differently, the shaded band shows a slower-to-faster clearance range rather than a single line. Absorption is simplified to "at the time you drink it" (real levels peak ~30–45 minutes later). The ~50 mg sleep-sensitivity guide is a working figure from sleep-latency research; the 400 mg daily reference for healthy adults comes from the FDA and Health Canada.
Educational, Not Medical Advice
Daily Vitality tools organize information and published guidance — they don't diagnose conditions, and they're not a substitute for care. Talk with your doctor, pharmacist, or another clinician about what's right for you.
Pregnant or breastfeeding? Published guidance is lower than the adult maximum — ACOG suggests under 200 mg a day and Health Canada no more than 300 mg — and your clinician's advice comes first.
Sources: brand nutrition/menu pages (Starbucks, Dunkin', Tim Hortons, McDonald's, Red Bull, Monster, CELSIUS, Coca-Cola, PepsiCo, and others) and USDA FoodData Central, seed values retrieved July 2026. Pharmacokinetics: average half-life ~5 h, individual range ~2–12 h (Institute of Medicine, 2014). Daily maximum: FDA & Health Canada, 400 mg for healthy adults. Pregnancy: ACOG (<200 mg/day); Health Canada (≤300 mg/day). This tool stores nothing you enter — your inputs live only in this page's URL.