Period & Ovulation Calendar

Go with your flow.

Track and predict your period and ovulation. Your symptoms, your notes and your intimacy life, in one calm place. Easy and uncomplicated.

an app that moves like you do · since 2008

iPhone Android

The background

18 years, one person.

Most apps like this one belong to a company. This one belongs to me. Here is how it happened, short version.

I really wanted to change something in my life. What came back to me was the advice of a friend and teacher: focus on supporting women.
2008 · Christian Albert Müller

2008 · Dahab

Between a fishing town and Romania

I had left Bavaria years before. I was travelling back and forth between Dahab, a fishing town on the Red Sea, and Romania, and I really wanted to make a change in my life. That is when I remembered the advice of a friend and teacher: focus on supporting women.

The first smartphones

I thought I could do that better

The first iPhone and Android phones were coming out. I started researching what was already there and found only very simple trackers. I thought I could do that better — with a calendar, with notes, with all of that. MyDays was born.

2013 and after

Then the years rolled

My daughter was born, and that was more exciting than code. I handed the app to freelancers and drifted away from the source while it kept running without me. Other apps copied it, some of them better looking than mine. That is the price of going first, and going first was still worth it.

2026 · now

Back at the keyboard

I came back because the tools finally let me build with the machine instead of against it. MyDays X has been rebuilt from the ground up, not painted over. Same calendar you know, underneath it a new app, on eighteen years of knowing what it is for.

There is no growth team here and no marketing department. When you write, it lands on my desk. That is either the charming part or the slow part, depending on the day.

Read the long version

Simple, on purpose

How you use it

There is not much to learn. Four things, and the rest you will find on your own.

Mark the day it starts

Tap the day your period began. That is the whole setup. Nothing else is needed before the app is useful to you.

Let it do the counting

The calendar shows the days it expects next and your ovulation, and tells you at a glance which day of your cycle you are on today.

Tap a day, add what happened

Symptoms, a note, intimacy, your blood pressure, pulse or blood sugar. A photo, if you want one. Only what you feel like writing down.

Look back when you need it

Your chart and your statistics, and a report you can export as a PDF and take to your doctor instead of trying to remember.

Lock it

A passcode, or Face ID, so the diary opens for you and not for whoever picks up the phone.

Back it up

Send an encrypted backup to your own email before every update. It stays yours — on your side, not ours. How that works.

In your language

Not only the menus. The symptom names, the daily cards, the reminders. That part took a while.

Write to me

There is a message thread to me inside the app. It comes straight to me, not to a ticket system.

More detail, and the questions people actually ask, are in the introduction and the FAQ. What happens with your data is written out in plain words in the privacy policy.

You decide

You picked this look

In July I spent two days playing art director instead of fixing bugs, and instead of one design, eight completely different ones fell out of it. Same app, same calendar, same hand. Eight personalities.

This app has been shaped by the women who use it for eighteen years, so it did not seem right to pick the front door alone. I put all eight up and asked which one felt like you.

Tap a name to try it on. Ocean won the vote — see the vote.

A tide runs on the moon, about twenty-nine and a half days to the round. A cycle runs close to the same length. I am not going to claim the two are connected. It is simply a rhythm you already know, and that is why the water fits.

Sunlight, deep water, and the pearl you have had in your pocket all along. The calendar inside stays exactly the one you know. Only the front door gets new paint.

The Ocean look: three panels of the MyDays X app store artwork, sunlit water above, deep blue below, and the calendar on a phone held in one hand. — The Ocean look, as it went to the vote on 28 July 2026.

What is coming

The big one is being tested right now

The app has been rebuilt from scratch, with privacy, security and education as the priority, and without losing the touch of entertainment. Health should not be boring.

A group of testers is living in it every day and telling me what is still wrong. I fix it and hand it back to them. That is the whole method, and it is slower than a launch date.

When it is ready for everyone, it will be in your app store. Bringing your years across is the part I have worked hardest on, and I would still send yourself a backup before you update. No date from me here, and no list of promises.

no promises,
just results The same way it has gone since 2008. You will hear about it when it is done, not before.

One desk

Write to me

A question, something broken in the app, or a request about your data. Write, and I read it. If you are in the app already, the message thread in there reaches me the same way.

Write to me email@mydaysx.club