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Caffeine Cutoff Calculator
Calculate your caffeine half-life curve and find the best time to stop drinking coffee.
The time you want to fall asleep, not just get into bed.
How strongly caffeine tends to affect your sleep and energy.
Your go-to caffeinated beverage.
How many servings of your typical drink you have daily.
About This Tool
This caffeine half-life calculator works backwards from your bedtime to tell you when to stop drinking coffee, energy drinks, or tea. Caffeine has a half-life of 5 to 7 hours for most people, meaning half of your afternoon dose is still in your blood at bedtime. Pair this tool with our Sleep Cycle Calculator to time both your caffeine cutoff and bedtime for the best possible sleep quality.
How to Use
Enter your target bedtime, caffeine sensitivity level, your typical caffeinated drink, and how many you have per day. The caffeine cutoff calculator computes your ideal stop time, total daily intake, and how much caffeine remains in your system at bedtime. Use the cutoff as a hard stop each day.
FAQ
How does caffeine actually affect sleep quality?
Even if you fall asleep after caffeine, it significantly reduces deep sleep (slow-wave sleep). A study in the Journal of Clinical Sleep Medicine found that caffeine consumed 6 hours before bed can reduce total sleep by over an hour. Your recovery, hormone production, and cognitive performance all take a hit.
Does decaf coffee still have caffeine?
Yes. A typical 8-ounce cup of decaf contains 2 to 15 milligrams of caffeine. While far less than regular coffee, highly sensitive individuals may still notice an effect from multiple cups. If caffeine keeps you wired, be mindful of decaf in the evening and use our Sleep Cycle Calculator to optimize your schedule.
Can you build a tolerance to caffeine?
Yes, regular use leads to tolerance — you need more for the same alertness boost. However, tolerance does not change how caffeine affects your sleep architecture. Even habitual coffee drinkers experience reduced deep sleep from late-day caffeine. Your brain adapts to feeling alert, but sleep quality still suffers.
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