01
Your cutoff, from your nights
Sleep data from Apple Health is compared across higher- and lower-caffeine nights. The cutoff is an observation from your own records, not a published guideline or a safe limit.
Caffeine tracker app for iPhone and Apple Watch
Find the cutoff your sleep records suggest
With optional Body Insights on, Caffeine compares your recorded sleep on higher- and lower-caffeine nights. After 21 nights, it may show a personal estimate or say there is no clear difference.
See how it works02
Preview before you log
Choose a drink, amount, and time. Compare the current bedtime estimate with the proposed drink before saving it.
03
Use a clear model
Estimates use an adjustable half-life model with a four- to six-hour reference range. They are not measurements of caffeine in your body.
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. Sleep also changes for many reasons. An observed difference does not show that caffeine caused it or establish a safe limit.
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.
Questions
Caffeine tracker FAQ
Is there a caffeine tracker app for iPhone and Apple Watch?
Yes. Caffeine Tracker: Bedtime lets you log drinks on iPhone or Apple Watch and shows estimates of what may remain in widgets and watch complications.
When should I stop drinking caffeine before bed?
There is no single answer, so the app lets you preview a drink first. Choose a drink, amount, and time, then compare the current and proposed bedtime estimates before you log it. With optional Body Insights on, it may estimate a personal cutoff from your own sleep records after 21 nights, or say there is no clear difference.
How long does caffeine stay in your system, and how does the app estimate it?
The app models each dose with exponential clearance and an adjustable half-life, 5 hours by default, with a 4 to 6 hour reference range. These are estimates, not measurements of caffeine in your body, and people differ.
Is this a caffeine half-life calculator?
In effect, yes. It applies the formula remaining = dose × 0.5^(elapsed ÷ half-life) to every drink you log and adds the results into a current and bedtime estimate.
Does the caffeine tracker work with Apple Health?
Yes. It uses Apple Health for caffeine records and sleep data, and you control which Apple Health sources count toward the timeline.
Is the caffeine tracker free, and does it need an account?
Core tracking and forecasting are free, with seven days of history, and no account is needed. Caffeine+ is an optional upgrade for full history and trends, and prices are shown in the app before you buy.
Can the app tell me a safe amount of caffeine?
No. It shows modeled estimates only, not blood measurements, safe limits, medical advice, or a guarantee about sleep. An observed difference in your sleep does not show that caffeine caused it.