Zyklus190924 | An offline, minimal fertility tracking app.

Zyklus is an offline, minimal fertility tracking app for mobile devices. It offers an overview of the current cycle phase, estimateds your fertility and keeps you in control and responsibility of your data.


Use Zyklus at your own risk!

The calendar method is a natural fertility awareness method (FAM). FAMs neither protect you from sexually transmited deseases (STDs) nor are they a reliable measure for birth control.

Find more information here.

Getting Started

Zyklus is a PWA - a Progressive Web App. Instead of downloading the app from a digital store, all you need to do is to browse to https://rostiger.github.io/zyklus/ with your mobile device and add the website to your Homescreen.


The app stores all your data locally on your phone. The advantage is that you don't need to be online to use it and the data doesn't have to be transmitted to servers run by companies you don't know.

The downside is that if your phone gets lost you will also loose all your data. This means, you will want to create backups from time to time.

In the settings section, there is a button to export your data. It will be stored as a plain text file, so make sure to store it in a safe location.


Zyklus supports the Hundred Rabbits Themes System