When to stop caffeine before bed
It depends on the drink, your bedtime, and how quickly you clear caffeine. Set those here and you'll get the latest time you can have it and still go to bed under your target.
Latest time for a coffee
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Set your bedtime to see your cutoff.
How fast you clear caffeine
How much is OK at bedtime
Latest times for common drinks
At your settings above. Tap one to see it in full.
Already had caffeine today?
The tracker logs what you've actually had and shows what will still be in your system at bedtime. Anything you log there counts towards the times on this page.
What it tells you
Pick a drink and the calculator gives the latest time you could have it and still be under your bedtime target for the whole night, not just at the moment you lie down. The list shows the same answer for common coffees, teas, and energy drinks, and anything you have logged in the tracker today is counted too.
How it works
The estimate uses the drink’s caffeine amount, the time you had it, your bedtime, and a half-life setting. A half-life is the time it takes for roughly half of the caffeine to clear. SlumberBrew also models the short rise after drinking instead of treating the dose as instant.
This is a personal estimate, not a universal rule. Coffee strength, serving size, metabolism, medication, pregnancy, and other factors can change the result.
Why your cutoff is personal
Caffeine clears at different rates. A coffee that is fine for one person in the afternoon may still affect someone else at bedtime. The calculator lets you pick a faster or slower half-life so you can use a more realistic starting point.
Related caffeine guides
How long does caffeine stay in your system? explains half-life and clearance. How much caffeine is in coffee? covers serving sizes and why brewed coffee varies. How much caffeine should you have? looks at dose and timing together.
Common questions
How long does caffeine stay in your system?
It depends on your half-life and the amount you drank. Caffeine does not disappear at one fixed time: the amount gradually halves, so a small remainder can persist well after the noticeable boost has faded.
Is there one safe cutoff time for everybody?
No. The calculator gives you a chosen bedtime target, not a medical safety line. If you have a health condition, take medication, are pregnant, or are worried about caffeine or sleep, ask a doctor.
Why does SlumberBrew give a range for brewed coffee?
The same named drink can contain very different amounts of caffeine. The times here use typical servings; the brew calculator in the tracker works from how you actually made yours and shows the uncertainty instead of a false exact number.
Sources and limitations
The model and its explanations draw on published research about caffeine half-life, individual variation, absorption, and sleep. See the science and method page for the full list of sources. SlumberBrew is not a medical device and none of its estimates are medical advice.
Read the science and method · Read how caffeine may interact with sleep · Read more support questions