Caffeine Curfew app

A quick tool to find a rough caffeine cutoff so an afternoon cup does not cost you sleep. Pin it to your home screen: on iPhone tap Share then Add to Home Screen; on Android tap the menu then Add to Home screen. It works offline once your browser has loaded it.

Want the full picture, including how much caffeine is in specific drinks? Use the caffeine comparison tool and the full curfew calculator.

A common rule of thumb is a caffeine half-life of about 5 to 6 hours, but it varies a lot by person. The FDA cites 400mg a day as the amount not generally linked to negative effects for healthy adults. This is general information, not medical advice.