[ tool ]
Caffeine calculator
Log what you drink throughout the day and watch the caffeine clear in real time. Built on an average caffeine half-life, which is cited as roughly 5 hours. Though your own metabolism, sleep, and stress all shift the real number.
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Active caffeine right now0mg
Sleep-safe fromAlready clear for sleepThe point where active caffeine drops under 50mg, roughly half the 100mg dose a 2025 clinical trial found with no measurable effect on sleep.
Daily caffeine limit0%The FDA cites 400mg of caffeine a day as the safe limit for a general adult.
How this is calculated
Each drink is tracked as its own dose and decays on its own from the moment you log it, using an average 5 hour half-life. We add up every active dose to get your current level. But remember, this is a simplification, not a lab test.
[ precision, not vibes ]
You just did the hard part.
Most people guess their caffeine dose. You just calculated yours to the milligram. We're building a coffee that starts from that number.