Periodical

Arno Welzel

About this app

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.

Ratings and reviews

Private, no frills app; I've used it for years. Being offline and having a neutral color scheme were the primary reasons I chose Periodical over other apps. I personally find it pretty accurate but it depends on your body chemistry. While it does predict your ovulation window I do wish it had a system for actually adjusting the predictions based on user data, like opk test results. I used a different app for a while that did this but came back to Periodical when that one broke.

Very good app, pretty accurate, has some additional info (mood & symptoms) if you need to track it. No ads, no fees, no cloud storage—it'salmost perfect! I wish there was some kind of password/pin lock, but I can live without. I tried almost all period tracking apps, and I can say this one is of the best. Edit: it's gender-neutral, too, which is a huge thing for myself.

For what I need -- very basic period tracking -- Periodical is perfect: two taps every month are enough to track what I want to, and no worries that my data is being sold or stolen. I used to use Clue and am so glad not to be bombarded with ads to upgrade or have to click through an endless series of buttons in order to track a single day.

What’s new

A cycle can start without change of the average calculation.