Flo, Clue, Glow and Leap compared for periods, ovulation and pregnancy — predictions, fertile windows and privacy, with paywall and reliability caveats.
The store charts list dozens of cycle, ovulation and pregnancy trackers, yet most withhold the basics — fertile-window estimates, symptom logs or week-by-week guidance — behind subscription walls, which is hard to accept for data you type in yourself. Below, the category's most downloaded app gets a full review based on what it actually delivers for free. The FAQ handles the questions that matter more than any feature list: whether fertile-day predictions are reliable enough when planning pregnancy, how cycle data is protected under European privacy rules, and the point at which an app should give way to a gynaecologist.
Flo is the most downloaded women's health app — over 460 million users — predicting periods, fertile days and ovulation and tracking pregnancy weekly.
Predictions come from your logged cycle history and sharpen when cycles are regular, while the app also records symptoms in detail and follows pregnancy week by week, with more than 100 health professionals involved in its content. Privacy-sensitive users get an anonymous mode that separates identity from health entries. The free experience is the weak point: the most useful features are paywalled, the upsell to Premium is aggressive, and users repeatedly report free functions disappearing in updates, so approach the free tier as a trial of the core calendar.
Pros
100M+ downloads, the world's most used tracker
Week-by-week pregnancy tracking
More than 100 health professionals on the team
Cons
Most useful features are paywalled
Aggressive upselling to Premium
Users report free features removed in updates
Download price only. In-app purchases and subscriptions may cost extra.
Questions & answers
What is the best free app for tracking the menstrual cycle?
Flo and Clue are the most complete in their free versions, although both have restricted features in recent years. If you want basic functions without paywalls, Leap Fitness Period Calendar is the strongest completely free option, with a 4.8-star rating and more than 10 million downloads. For anything beyond logging dates, expect the bigger names to push a subscription.
Are these apps safe for my privacy?
Clue has the strictest position, headquartered in Berlin and operating under European GDPR. Flo offers an Anonymous Mode that disconnects your name from health data, and the apps encrypt data in transit, but you should always read the policy before using one. Check whether registration is genuinely optional, avoid social login, and prefer local-only storage if syncing is not important to you.
Are these apps reliable when trying to get pregnant?
They are useful for logging cycles and estimating the fertile window from your own data. But the predictions are statistical estimates: irregular cycles, stress or weight changes throw them off easily, so they do not replace a gynaecology consultation. If you have been trying to conceive without success for some time, the sensible move is to see a professional rather than trust an app's calendar.
What happens to the privacy of my cycle data?
It is especially sensitive health data and should be treated that way. Read the privacy policy before registering, check whether the app offers an anonymous mode or local-only storage, and be wary of services that demand linking social networks. Several of these apps have introduced stronger privacy modes following criticism in recent years, which is progress, but it does not make the data any less sensitive.
More related apps
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