Coffee Cutoff is a free calculator that tells you when to have your last coffee so caffeine doesn't cut into your sleep. Enter your wake-up time and it works out a bedtime based on 90-minute sleep cycles and a caffeine cutoff based on how strongly caffeine affects you.
How the numbers are worked out
Bedtime is your wake-up time minus the number of 90-minute sleep cycles you choose, minus about 15 minutes to fall asleep. The coffee cutoff is 6, 8 or 10 hours before that bedtime, depending on your caffeine sensitivity. Caffeine has a half-life of roughly five hours, and a 2013 study in the Journal of Clinical Sleep Medicine (Drake et al.) found that caffeine taken six hours before bed still reduced total sleep by more than an hour.
Who runs it
Coffee Cutoff, an independent website run from Hungary. The goal is simple: a fast, useful tool you can come back to, without sign-ups.
Not medical advice
Everything on this site is general information. If you have ongoing sleep problems, are pregnant, take medication or have a health condition, talk to a doctor.
How the site is funded
The calculator is free. The site may show ads and include affiliate links to products we think are useful. That never changes the numbers the calculator gives you.
Questions or ideas? Write to [email protected].