Caffeine Cutoff Calculator
Find the latest time you can have caffeine without disrupting your sleep.
Genetics, pregnancy, and some medications affect how fast you metabolize caffeine. When in doubt, choose "Normal."
Your last safe time for caffeine is
Based on bedtime at 10:00 PM
Caffeine remaining in your system at bedtime:
No caffeine detected. Your sleep should not be affected.
Your caffeine timeline today
Caffeine before the cutoff is fine — most will clear by bedtime. Caffeine after the cutoff will interfere with your sleep.
☕ Caffeine content in common drinks
🛍️ Evening Wind-Down Essentials
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How the cutoff works
Caffeine has a half-life of roughly 5–8 hours in most adults. That means if you drink 100 mg of caffeine at 2 PM, about 50 mg is still active in your system by 8 PM — enough to disrupt sleep for many people.
This calculator uses your chosen half-life and bedtime to estimate how much caffeine remains when you hit the pillow, then finds the latest safe time so the amount left won't keep you awake.
For a deeper dive, read our complete guide to caffeine cutoff times.