Flo Zyklus- & Periodenkalender

What the Flo period and cycle calendar covers

Flo Zyklus- & Periodenkalender is a period, cycle and ovulation calendar that also covers pregnancy and perimenopause. It is aimed at people who want to follow their menstrual cycle over time, whether the cycle is regular or irregular.

The developer, Flo Health Inc., describes the app as science-backed and says it has been downloaded more than 570 million times worldwide.

Predicting ovulation and learning fertile signs

The app predicts ovulation and is meant to help a user learn to spot their own fertile signs. The developer presents this as part of cycle tracking for both regular and irregular cycles.

Pregnancy tracking and perimenopause symptoms

A pregnancy tracker follows the changes to the baby and to the body over the course of a pregnancy. Separately, the app lets users explore common perimenopause symptoms.

Pill reminders in the same app

The app's summary also names a pill reminder, so it can prompt a user to take pills on schedule alongside the period calendar.

Anonymous Mode, Secret Chats and data protection

Anonymous Mode lets a person use the period tracker without linking a name, email or other personal identifiers. Secret Chats is a space to connect with other members who share tips and personal experiences.

The developer states that the app holds ISO 27001 and ISO 27701 certifications, and that Flo was recognised as ISO 27001 Information Security Management System Team of the Year at the 2025 PICCASO Privacy and Security Awards. These are the developer's own claims.