01
Choose a dose
Start with a quick amount or enter the caffeine on the label. Change the drink time if you are planning ahead.
Caffeine with a bedtime forecast
Preview the next drink before you log it
See what may remain now, what may remain at bedtime, and how another coffee could change both estimates.
See how it works02
Compare bedtime
See the existing forecast beside the forecast with the proposed drink. A 4 to 6 hour range keeps the uncertainty visible.
03
Decide, then log
The preview is useful even when the answer is no. If you log it, Apple Health keeps the intake timeline available across devices.
A clear model
Useful estimates without false precision
Each dose is modeled independently with exponential caffeine clearance. The default half-life is 5 hours and can be adjusted. The app shows estimates, not blood measurements or guarantees about sleep.
remaining = dose × 0.5^(elapsed ÷ half-life)
Built into your routine
Phone, wrist, widgets, and Apple Health
Log from iPhone or Apple Watch, check the current and bedtime estimates in a widget or complication, and control which Apple Health sources count toward the timeline.