Your Caffeine Curve

See exactly when caffeine stops ruining your sleep — based on your actual drinks.

Add your first drink to see your curve

Already below threshold — sleep anytime tonight

Sleep-safe threshold: 25 mg

A conservative guideline — adjust based on how caffeine-sensitive you are.

Your drinks

No drinks logged yet

5 hours

Caffeine half-life used

25 mg

Default sleep-safe threshold

How the curve is calculated

Each drink adds caffeine to your bloodstream at the time you logged it.

Caffeine has a half-life of about 5 hours — every 5 hours, half of what is in your system is cleared. This is a well-established pharmacokinetic average; your personal rate varies.

We plot the running total across your day. When the curve crosses your threshold, that is your earliest sleep-safe time.

This is a guideline, not a clinical diagnosis. Individual caffeine metabolism varies with genetics, body size, pregnancy, and medications.

Sources & assumptions

Source	Detail
Caffeine per drink type	FDA Caffeine Content of Food & Drug chart + EFSA Comprehensive European Food Consumption Database.
5-hour half-life	Standard value cited in peer-reviewed pharmacokinetics literature (e.g., Mandel, 2002; FDA CFSAN review).
25 mg default threshold	Informed by sleep-study literature suggesting caffeine doses as low as 50mg can measurably affect sleep onset in sensitive individuals; we default lower to be conservative. Adjust to match your body.
Privacy	No data leaves your device — all calculations run locally in your browser.

All values from FDA/EFSA published charts

Use this before nights that matter

Big morning tomorrow? Log what you plan to drink today and see if your curve clears your threshold in time. Adjust your last drink or move it earlier — then check the new safe-sleep time in one glance.