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Halfsip Support
Tap what you drank, and see on a curve when the caffeine in your body will fall to a level generally considered sleep-friendly.
Before that late-afternoon coffee, long-press it to see "what if I drink this now" — the curve and the estimated time shift before you decide. All numbers are estimates, and your log stays on your device.
Halfsip shows estimates based on average values. It is not medical advice. Caffeine affects people very differently depending on individual factors, pregnancy, medication, and more. If you have concerns, please consult a doctor.
Halfsip uses a common simple model: caffeine is absorbed over roughly the first hour (absorption half-life about 15 minutes) and then eliminated with a half-life you can set (default 5 hours, adjustable from 3 to 8 hours). You can read the details in "About this curve" in the app. Real-world values vary from person to person.
It is the amount below which caffeine is generally considered less likely to affect sleep (default 50 mg). You can change it in Settings. The moon mark shows the estimated time the curve falls below this line.
400 mg is a commonly cited daily reference for healthy adults (for example, by the U.S. FDA). It does not apply to everyone, including during pregnancy. Halfsip shows it only as a reference.
Preset amounts are typical values and vary by product, size, and brewing method. You can edit the amount when logging, and with Halfsip Pro you can save your own drinks.
- Free: logging with drink presets, the curve, the estimated time, "what if I drink this now", and today's total
- Halfsip Pro (one-time purchase): home and lock screen widgets, your own drinks, writing to Apple Health, history, and an optional evening reminder (buy once, keep forever)
From Settings, use "Restore Purchases" to restore purchases made with the same Apple Account.
Your log is stored on your device (there is no cloud sync). If iOS "iCloud Backup" is enabled, Apple's system includes this app's data in your device backup, so it can be restored on a new phone. Deleting the app deletes the on-device data.
For bug reports and requests, please let us know via Issues.
When reporting, it helps to include:
- Your device (e.g., iPhone 15 Pro) and iOS version
- The app version (shown at the bottom of the Settings screen)
- What you did and what happened