Flo Ovulation & Period Tracker

Flo tracks the menstrual cycle across the whole of reproductive life rather than one stage of it. Periods are logged whether regular or irregular, ovulation is predicted, and the app helps you recognise your own fertile signs rather than relying only on a calendar calculation, which is where simple cycle apps are least reliable. A pregnancy mode follows changes to your body and the baby week by week, and a perimenopause section covers the symptoms of a stage that is widely experienced and poorly explained. More than five hundred and thirty million downloads sit behind it. Data protection deserves specific mention here, because reproductive health data is more sensitive than most and the consequences of it being mishandled are more serious. Flo holds dual ISO 27001 and ISO 27701 certifications, which are the internationally recognised standards for information security and privacy management, and it is the only period tracking app to hold both. Tracking symptoms alongside dates is what makes the app useful over time: patterns in mood, pain, sleep and energy across cycles become visible, and that record is genuinely valuable in a medical appointment.