Quiz
Caffeine Cutoff Calculator
Work backward from your bedtime to the last hour you can safely have caffeine. Adjusts for how sensitive you are, because the famous "no coffee after 2pm" rule fits almost nobody.
"No caffeine after 2pm" is a number somebody made up. Your actual cutoff depends on one thing: when you intend to be asleep.
Caffeine's half-life is five to six hours, so a dose at 2pm is still a quarter-strength dose around midnight — enough to suppress deep sleep without stopping you falling asleep, which is exactly why people sleep eight hours and wake unrestored. Set your bedtime and your sensitivity below.
Common questions
What time should I stop drinking coffee?
Work backward from when you intend to be asleep, not forward from lunch. Eight hours before bed is the minimum, ten is the sensible default, and twelve suits people who are genuinely caffeine-sensitive. For an 11pm bedtime that is somewhere between 11am and 3pm.
Why is the "no caffeine after 2pm" rule wrong?
It is not wrong so much as arbitrary — it only fits one bedtime. Someone asleep at 9:30pm and someone asleep at 1am need very different cutoffs, and the rule ignores both sensitivity and dose.
Does caffeine really affect sleep if I fall asleep fine?
Yes. Falling asleep and sleeping well are different things. Caffeine still in your system suppresses deep slow-wave sleep without necessarily delaying sleep onset, which is why people sleep a full night on it and still wake unrefreshed.
Not medical advice. This is a self-assessment for general information, not a diagnostic test. If you snore loudly, have witnessed pauses in breathing, gasp awake, or feel exhausted no matter how long you sleep, see a doctor — those warrant a proper assessment rather than a questionnaire.