The best private period tracker apps in 2026

Most "best period tracker" lists rank apps by features — fertility predictions, partner sharing, mood charts, AI summaries. This one doesn't. It ranks the six most-installed private period tracker apps in 2026 by exactly one thing: what happens to your cycle data once you log it.

If you care about whether your period app sells your data, hands it to ad networks, or stores it on a server that could be breached, this is the comparison you actually need. We'll tell you where Dew sits in the list, but we'll also tell you when another option fits you better.

The single test that matters

For each app, we asked one question:

Where does your cycle data live, and who else can read it?

Everything else — features, design, price — is a tiebreaker. A beautifully designed app that ships your luteal phase to an ad network isn't private. A clunky app that stores everything offline is.

The six apps, ranked

1. Dew — fully on-device, no server

What it stores, and where: All cycle data lives in the app's local sqlite-data database on your iPhone, and (optionally) in your own iCloud Private Database. Dew has no servers. There is no Dew account, no email, no profile. You cannot sign in even if you wanted to.

Who else can read it: Nobody. Not Dew. Not Apple (your iCloud Private Database is end-to-end encrypted with your iCloud keys). Not advertisers. Even on subpoena, Dew has nothing to hand over because Dew never has it in the first place.

Trade-off: No cross-platform — iOS only. No partner sharing yet (planned for v1.1). If you want a tracker on Android, scroll down to Drip.

2. Apple Health Cycle Tracking — on-device, by Apple

What it stores, and where: All cycle entries live in HealthKit on your iPhone, end-to-end encrypted in iCloud if sync is enabled.

Who else can read it: Nobody, including Apple. HealthKit is end-to-end encrypted; Apple has stated publicly they cannot read it. Cycle tracking data has its own "extra-sensitive" classification within HealthKit (alongside sexual activity) that requires a re-authentication to access.

Trade-off: The UI is functional, not delightful. Predictions are basic. No symptoms beyond a fixed list. No notes longer than a sentence. If you want privacy + minimal features, this is the right answer. If you want privacy + a real diary, keep going.

3. Euki — fully offline, no cloud option

What it stores, and where: Everything stays on your device, full stop. No optional iCloud sync, no account, no anything. You can hide the app inside the OS (it disguises as a calculator).

Who else can read it: Nobody. There's no possible mechanism — no network code in the app.

Trade-off: You lose everything if you lose your phone. There is no backup, no restore, no sync to your other devices. For users in jurisdictions where cycle data is being actively subpoenaed, this is intentional and correct. For most users, it's painful.

4. Drip — open source, offline by default

What it stores, and where: Locally on the device. Optional backup to your own iCloud or Google Drive in an encrypted file. The app is open source — anyone can audit the code.

Who else can read it: Nobody by default. The optional backup is encrypted with your password.

Trade-off: Available on both iOS and Android (the only one in this list besides Euki that runs on both). The UI is functional rather than calm — it looks like what it is, an open-source community project.

5. Clue — cloud-stored, with privacy claims

What it stores, and where: On Clue's servers in Germany. Tied to an account (email required).

Who else can read it: Clue's privacy policy says they don't sell your data and they're GDPR-bound (German jurisdiction, strict). They have shared anonymized aggregate data with research partners (Stanford, Oxford). Account deletion is honored.

Trade-off: If you trust German data-protection law and Clue's track record, this is a reasonable middle ground. If you don't want the data on anyone else's server, don't pick it.

6. Stardust — cloud-stored, sketchier history

What it stores, and where: On Stardust's servers.

Who else can read it: Stardust has been called out (notably by The Markup in 2022) for sending data to third parties despite marketing privacy. The company has updated practices since, but trust takes time to rebuild.

Trade-off: Beautiful UI, large user base, astrology-themed framing that some love. We don't recommend it for the privacy-first case.

How to choose

• You want the calmest, most-private iOS tracker: Dew.
• You want bare-minimum private tracking and already trust Apple: Apple Health Cycle Tracking.
• You're in a jurisdiction where cycle data could be subpoenaed: Euki, or Apple Health (Apple has stated they will not honor subpoenas for E2E data because they technically cannot decrypt it).
• You want open source + Android: Drip.
• You want cloud sync with a credible privacy posture: Clue.

What we'd skip in 2026

Apps with ad networks in the privacy policy (Flo before the FTC settlement, several smaller free trackers), apps tied to attribution SDKs (Adjust, AppsFlyer, Branch), apps that gate basic features behind a sign-up that demands real-name fields.

For a deeper look at the comparison mechanics, see Flo, Clue, Stardust, Dew: a privacy comparison and How to find a period tracker that doesn't sell your data.

If you only remember one thing

The most private app is the one with the smallest possible attack surface — no account, no server, no third-party SDKs. On iOS in 2026, that's Dew or Apple Health.