How to find a private period tracker

A period tracker knows when you bleed, how you feel and whether you’re trying to get pregnant. A private period tracker keeps that to you and the people you choose. You can’t see inside an app, but you can check a few things before you trust it with your first log, starting with its App Store listing.

Start with the privacy label

Every listing has an App Privacy section, filled in by the developer, who is responsible for keeping it accurate (Apple). It sorts what an app collects under three headings:

• Data Used to Track You may be combined with data from other companies’ apps and websites for targeted ads or measuring them, or shared with data brokers.
• Data Linked to You is collected and tied to your identity.
• Data Not Linked to You is collected, but not tied to who you are.

For a period tracker, two entries say the most. Health & Fitness under Data Linked to You means the health data you log is tied to your identity. Contact Info there means the app collects your name, email address, phone number or the like, and ties it to you. A label that reads Data Not Collected means the developer collects nothing from the app at all.

What 8 popular trackers’ labels say

We took the eight apps with the most ratings among the first 30 results of a US App Store search for “period tracker”, and read their labels on November 3, 2026. Fia, which we make, is at the bottom for comparison.

Six of the eight tie the health data you log to your identity, and six list data used to track you. Stardust and My Cycle keep health data unlinked, and My Cycle is the only one of the eight that lists neither tracking nor contact info. Flo’s label doesn’t show its Anonymous Mode, which stops linking your identity to your health data (Flo). Fia as a Flo alternative compares the two.

Five more things to check

1. Does it need an account? An account ties your logs to your email address or phone number. A period tracker with no account goes through what changes without one.
2. Where are its predictions worked out? On your phone, or on the company’s servers, as its privacy policy should say. Fia works out your next period on your iPhone, from the periods you log (why it shows a range).
3. What has it been found doing? Of the 23 most popular women’s health apps in one review, 20 shared user data with third parties Alfawzan et al., 2022. In 2021, the US Federal Trade Commission alleged that Flo had shared sensitive health data from millions of users with companies including Facebook and Google, after promising to keep it private. Flo settled FTC, 2021.
4. Who starts sharing, and can you stop it quietly? California’s Attorney General settled with one fertility app whose partner feature, until 2016, linked anyone who asked California Attorney General, 2020. Researchers recommend letting people change what they share discreetly Levy and Schneier, 2020.
5. Can you delete everything yourself? Look for a way to do it inside the app, not only by email.

The private option already on your iPhone

If all you want is a log and a prediction, Cycle Tracking in Apple’s Health app may be enough. It predicts your next period and estimates your fertile window, and with Apple Watch Series 8 or later, or any Apple Watch Ultra, it can use your wrist temperature to estimate when you likely ovulated (Apple). Apple end-to-end encrypts the Health data you sync to iCloud, so Apple doesn’t have the keys to read it (Apple).

Fia works alongside it. Connect Apple Health, and Fia reads the periods you’ve logged there, and can save the ones you log in Fia.

What Fia adds to a private log

Fia’s label says Data Not Collected: it has no account, no ads and no analytics, and nothing you log comes to us. On top of the log, it:

• shows your next period as a range of days, and says which cycles it’s based on;
• answers your check-ins with what your own logs show, looking back, and names a pattern only once it has held for four cycles;
• makes your cycle record and a one-page PDF summary for your doctor, on your iPhone;
• guides your kegels from five minutes a day, with weeks 1 to 4 free;
• shares a summary you choose with up to five people you invite, from your iCloud to theirs, never through us Apple.

What “Data Not Collected” means explains where your logs live, and what leaves your iPhone only if you choose.