Periodical

A menstrual calender with calculation of fertile days according to Knaus-Ogino.GPL-3.0-or-later

drip period & cycle tracker

Open-source, non-commercial and leaves your data on your phone.GPL-3.0-only

Bluemoon

Open source, privacy friendly menstruation tracking app. Your period, your data!GPL-3.0-or-later

Luteal

Private, offline-first cycle tracker separating facts from estimatesGPL-3.0-or-later

Ebb

A period tracker that keeps your cycle on your phone. No account, no internet.GPL-3.0-or-later

Mooneva Cycle – Period Tracker

Private period & cycle tracker. Offline, encrypted, no account, no ads.GPL-3.0-only

NER Cycle App

Local cycle evaluation per the NER rules (Rötzer) — data stays on device.Apache-2.0

Mensinator

Tailored Period Tracking, Total Privacy—Your Period, Your Control.MIT

Noor Connect

Privacy-first Islamic companion: Quran, prayer times, Qibla, hadith & more.GPL-3.0-only