Open-source period trackers

4 period trackers whose code is public under an OSI-approved license, rated for privacy with evidence. Picks first, then by score.

1. drip. Grade B

   Open source menstrual cycle tracker for Android and iOS that supports the symptothermal method and keeps all data on the device.

   GPL-3.0. Source code

2. Mensinator Grade B

   Open source Android period tracker with custom colour-coded symptoms, cycle and ovulation predictions, and data export, with no sign-up and no network access.

   MIT. Source code

3. Periodical Grade B

   Open source Android period calendar that estimates fertile days with the calendar method, with notes, symptoms and local backup.

   GPL-3.0. Source code

4. Euki Grade C

   Open source sexual and reproductive health app from a US nonprofit, with period tracking, reminders and health information. Data stays on the device, with an optional PIN.

   GPL-3.0 for the Android and iOS apps. Source code

Compare all 8 period trackers, open source or not.