Tools · caffeine clearance · an honest estimate, not medical advice
Still Awake
Log what you drank and when, and see how much caffeine is likely still in you
across the evening — drawn as a band, not a fake-precise single time, because how fast you
clear caffeine genuinely varies. Every number is cited; it runs entirely in your browser; and it
adjusts the band for the few things that really move it (smoking, estrogen contraception, pregnancy).
This is an educational estimate built from population averages — not medical advice,
not a clinical tool, and not about you specifically. Your own clearance depends on genetics (CYP1A2),
tolerance and sensitivity that no calculator can know. See the honest limits below.
1 · what did you drink, and when?
Add a drink to begin. Each one defaults to the current time — change it to when you actually had it.
100 mg
A reference you choose — not a medically-safe floor. No study defines one;
a large dose disrupts sleep even 6 h later (Drake 2013).
caffeine likely still in you (fast → slow metabolizer)your reference levelbedtime
Lift the hood — the model, the half-lives, the caveats