Periodical
Periodical Summary
Periodical is a mobile Android app in Health And Fitness by Arno Welzel. Released in Apr 2012 (14 years ago). It has about 25.6K+ installs and 166 ratings with a 4.50★ (excellent) average. Based on AppGoblin estimates, it reaches roughly 621 monthly active users . Store metadata: updated Apr 19, 2026.
Recent activity: 81 installs this week (282 over 4 weeks) showing below average growth , and 1.00 new ratings this week View trends →
Store info: Last updated on Google Play on Apr 19, 2026 .
4.5★
Ratings: 166
Screenshots
App Description
A menstrual calender with calculation of fertile days according to Knaus-Ogino.
This application calculates the fertile days according to Knaus-Ogino and can track menstrual symptoms.
WARNING: It is not recommended to use this calendar to avoid pregnancy! There are more accurate methods, like measuring the basal body temperature.
The data can be backed up on a memory card or "internal" memory, if present.
If you have any further questions or want to help me with translations in other languages, please contact me via e-mail - thank you.
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
You can obtain the source on my website.