Editor's Review
Clue asks for a small amount of input each day, bleeding, pain, mood, energy, whatever else you choose to record, and turns it into a picture of your cycle over months rather than a single prediction. That framing is the point. It was built with input from reproductive health researchers and tends to describe ranges and patterns instead of promising a date.
The tracking categories are broad and mostly optional. Past period days and flow you can log cramps, headaches, sleep, exercise, skin, digestion, sex and contraception use, and the app begins showing which of these cluster around particular phases. For anyone preparing for a GP or gynaecologist appointment, an exported few months of that beats trying to remember. Reminders cover the period itself, PMS and pill-taking.
Clue Plus is the subscription layer and carries the deeper analysis: phase-linked content, more detailed insights, and additional modes such as pregnancy or perimenopause. The free app is still a working tracker without it, which is more than several competitors manage, though the more interesting reading of your own data sits behind the paywall.
Two cautions. Prediction accuracy depends on regularity, so irregular cycles, PCOS, hormonal contraception and postpartum recovery all reduce the forecast to a rough guide, and the app is reasonably honest about that. And cycle data is sensitive. Clue is a German company subject to European data protection law and has been vocal about not selling personal data, a stronger position than most, but anyone uneasy about the legal climate around reproductive data should read the privacy policy themselves rather than trust a star rating. At 4.49 from 50M+ installs it is among the more credible options in a category full of ad-heavy imitations.
Features
Period, flow and cycle-length logging with predictions
Wide range of optional symptom, mood and lifestyle categories
Pattern analysis showing what recurs at each phase
Reminders for periods, PMS and contraceptive pills
Cycle history you can summarise for a medical appointment
Clue Plus subscription adding pregnancy and perimenopause modes
Pros
Research-led approach that offers ranges instead of false certainty
The free version is a complete tracker, not a trial
Symptom history genuinely helps in a doctor's appointment
A privacy stance stronger than most of the category, under European law
Cons
The more interesting insights are reserved for the paid tier
Predictions degrade badly with irregular cycles or hormonal contraception
Daily logging is a habit, and gaps weaken the whole model
Questions people ask
Can Clue be used as contraception?
No. It predicts from what you log and is not a certified fertility-awareness contraceptive method. Any app used to prevent pregnancy needs to be a regulated one, used exactly as instructed.
What does Clue Plus add?
The subscription unlocks deeper cycle analysis, content tied to your current phase, and specialised modes such as pregnancy tracking. Ordinary period and symptom logging stays free.
How sensitive is the data I put in?
Very. Cycle, sex and pregnancy logs are among the most personal categories there are. The company operates under European data protection rules and states it does not sell personal data, but read the current policy and decide what you are comfortable recording.
