Dose matters more than time
Gardiner et al. 2025 — RCT, 7 conditions
100mg caffeine: no measurable sleep effect at ANY timing (even 4h before bed). 400mg: disrupts sleep even at 12h before bed.
When should you drink coffee?
Most caffeine tools just tell you how much is left. We tell you when to drink it — based on when you need energy and when you sleep.
No account. No install. Evidence-based. Private by default.
Quick: When should I stop drinking coffee?
One drink + your bedtime → latest safe time. Based on dose-dependent cutoffs (Gardiner 2025).
How it works
Enter your bedtime
When do you want to be asleep?
Add alertness windows
When do you need focus? (e.g., 8–11am, 5–7pm workout)
Pick your drinks
Choose coffee, tea, or energy drink for each window
Get your personalized schedule
See exactly when to drink each dose, how much caffeine remains at bedtime (fast/slow metabolism range), and dose-dependent warnings.
Built on evidence, not guesswork
You can feel fine but sleep worse
Drake et al. 2013 — J Clin Sleep Med
400mg at 6h before bed reduced total sleep by ~1 hour. Subjects reported NO sleep disruption. Objective ≠ subjective.
Half-life varies 3–8+ hours
IOM 2001 / EFSA 2015
Population range 1.5–9.5h. CYP1A2 genetics: ~40% fast (~3h), ~10% slow (~8–10h). Single-number calculators are misleading.
Most tools ignore absorption
Pharmacokinetic standard
Caffeine peaks at 30–60 min. Drinking at 2pm means peak at 2:45pm. Simple calculators assume instant absorption.
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