This innovative Periodical app simplifies menstrual cycle tracking and fertility prediction. Using the Knaus-Ogino method, it accurately calculates fertile days and allows you to track symptoms for a better understanding of your cycle. Data backup ensures peace of mind, and the app is completely free to use under the GNU General Public License. The developer is readily available via email for questions or translation assistance. The app's open-source nature allows for transparency and customization. Download Periodical today for efficient and user-friendly cycle management and take control of your reproductive health. Key features include: fertility tracking via the Knaus-Ogino method; menstrual symptom tracking; secure data backup; and support for multiple languages.