Coffee Cutoff Time Calculator

Most sleep experts recommend stopping caffeine 8 to 10 hours before bedtime. However, your ideal cutoff time depends on your caffeine sensitivity, the specific drink, and how much residual caffeine your body can tolerate without affecting sleep. Use the calculator above to find your personalized cutoff time.

Caffeine sensitivity is determined by your CYP1A2 gene and affects how quickly your liver breaks down caffeine. People with low sensitivity (fast metabolizers) have a 4-hour half-life and can drink coffee later in the day. Those with high sensitivity (slow metabolizers) have a 6-hour half-life and need to stop much earlier to avoid sleep disruption.

There is no universal ideal cutoff time because it depends on your bedtime, drink choice, metabolism, and tolerance. For most people drinking a standard cup of coffee with normal sensitivity and a 10:30 PM bedtime, the cutoff falls between 1:00 PM and 3:00 PM. The calculator above gives you an exact time based on your personal inputs.

Yes. Decaf coffee still contains 2 to 15 mg of caffeine per cup. While this is far less than regular coffee (95 to 200 mg), it is not zero. For most people, decaf is fine in the evening. However, if you are highly sensitive to caffeine or drink several cups, even decaf can add up enough to affect your sleep quality.

Research suggests that even 25 to 50 mg of caffeine in your system at bedtime can reduce sleep quality, particularly deep sleep and REM sleep. You may not feel "wired," but your sleep architecture can still be affected. That is why this calculator defaults to a 50 mg target, a level most people can tolerate without significant sleep disruption.