Caffeine Curve: Can I Sleep?

Log your coffee in one tap and watch it decay in real time. Caffeine Curve tells you exactly when you'll be clear to sleep — and when it's time for your last cup.

Ever lie awake at 11 PM wondering if that 4 o'clock coffee was a mistake?

Caffeine Curve answers the question every coffee drinker asks: can I sleep tonight?

HOW IT WORKS Log your drinks with one tap — espresso, coffee, cold brew, tea, energy drinks, or anything custom. The app plots the caffeine level in your body as it decays hour by hour, and tells you exactly when you'll drop below your sleep threshold.

• See your live caffeine level and its full decay curve • A clear verdict: "You'll be under 50mg by 9:42 PM — clear for your 11 PM bedtime" • "Last call" reminder: a daily notification when your next coffee would start costing you sleep • Tune it to your body: metabolism speed, sleep sensitivity, and your own bedtime • Daily history with totals, so you can spot your patterns

PRIVATE BY DESIGN No account. No ads. No analytics. Everything you log stays on your phone — the app doesn't even have a server to send it to.

THE SCIENCE Caffeine has a half-life of roughly 5 hours (faster for some, slower for others). Caffeine Curve uses the standard exponential decay model to project your level forward — not medical advice, but a far better guess than "I feel fine."

One question. One curve. Better sleep.