Flo is a period and cycle tracking app made by Flo Health. Brothers Yuri and Dmitry Gurski founded the company, and the app launched in 2015. Flo Health is based in London and has a large team in Vilnius, Lithuania.
Users log their periods, symptoms, moods and other signs, and the app predicts their next period and fertile window. It offers a pregnancy mode with week by week updates and a mode for people going through perimenopause. A library of articles and short courses covers reproductive health topics, and content is reviewed by doctors and other experts. Anonymous Mode lets users use the app without linking data to their name, email or device identifiers.
Flo has a free version with core tracking. Flo Premium is a paid subscription that adds detailed health insights, guided courses and more content. In 2021 Flo settled a case with the US Federal Trade Commission over sharing health data with outside analytics firms, and it has since added privacy features. Flo runs on iOS and Android. It is one of the most downloaded health apps in the US and Europe.