Wondering when to stop drinking coffee so it doesn’t ruin your sleep? Enter your bedtime and caffeine sensitivity to get your personal caffeine cutoff time — plus an optional check of how much caffeine is still in your system at bedtime.
How to Use This Calculator
- Enter the time you go to bed.
- Choose your caffeine sensitivity: Standard or Sensitive.
- Click Find my caffeine cutoff and read your cutoff time below.
Try this: Bedtime 23:00 with Standard sensitivity. You will see a cutoff of 15:00. Add a last coffee at 15:00 with 2 cups to see about 63 mg left at bedtime.
The bedtime field starts filled in. If you clear it, no result appears until you pick a time again.
How sensitive are you to caffeine?
Optional: check caffeine left from your last coffee
This is an estimate only, not medical advice. Caffeine half-life varies from person to person (roughly 4–6 hours), and sources disagree on the ideal bedtime threshold — treat the cutoff as guidance, not a rule.
Frequently Asked Questions
Why stop drinking coffee 8 hours before bed?
Caffeine has a half-life of about 5 hours, so a meaningful amount can linger in your system for 8 hours or more. Many sleep sources recommend an 8–10 hour buffer so your last coffee doesn’t delay sleep or reduce sleep quality.
Does decaf coffee count toward the cutoff?
Decaf still contains a small amount of caffeine — a few milligrams per cup — so if you are sensitive to caffeine, it’s wise to observe the cutoff for decaf too.
Why does caffeine sensitivity matter?
People metabolize caffeine at different rates — the half-life is roughly 4–6 hours depending on the person — so sensitive sleepers benefit from the longer 10-hour buffer instead of the standard 8-hour one.