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Published by Floriva · Updated 2026-04-01 · How Floriva checks its guides
Best Period Tracker Apps in 2026
8 period trackers ranked by privacy architecture, features, and price. On-device, server-based, and open source options compared.
The best period tracker depends on how much you value privacy architecture over feature count. On-device apps (Floriva, Euki, Drip) never send data to a server, making them structurally safer post-Dobbs. Server-based apps (Clue, Natural Cycles, Flo) offer larger datasets and more features but create subpoenable records. Flo carries documented FTC enforcement history and a $59.5M settlement.
How to Evaluate a Period Tracker
Where your data lives matters more than feature count.
There are two architectures: on-device (data stays on your phone) and server-based (data is stored on the company's servers). That difference determines whether your reproductive health data can be shared, breached, or subpoenaed.
The FTC took enforcement action against Flo (2021) and Premom (2023). Both were server-based apps that shared data with third parties. On-device storage cannot be shared because no company server holds a copy.
Source: FTC vs. Flo, January 2021; FTC vs. Premom, May 2023
The Ranking Criteria
This list ranks apps by:
Data architecture, on-device vs. server-based
Enforcement history, documented regulatory actions or settlements
Transparency, open source, published architecture, third-party audits
Features, cycle prediction, symptom tracking, sync, platform support
Pricing, what you pay and what's behind a paywall
Privacy architecture carries the most weight. A feature-rich app that stores data on servers you do not control still creates subpoenable records.
On-Device Apps
On-device trackers store data on your phone. No company server holds a copy. That means no database to breach, no server to subpoena, and no path for undisclosed data sharing.
Consumer Reports recommended on-device trackers, specifically Drip, Euki, and Periodical, as apps that "store data locally and don't allow third-party tracking."
Source: Consumer Reports, August 2022
Server-Based Apps
Server-based apps store your data on company infrastructure. This enables automatic backup and multi-device access, but it also creates a permanent record. That record can be accessed through legal process, data breaches, or policy failures.
GDPR-compliant apps like Clue offer stronger protections than US-based apps, but GDPR does not block lawful data requests from courts. The protection is real but not absolute.
The FTC Precedent
Two period and fertility tracker apps have faced FTC enforcement: Flo (2021) and Premom (2023). Both were server-based. Both shared data with third parties despite privacy policy claims to the contrary.
Flo's case resulted in a $59.5M combined settlement in 2025. The Bureau of Investigative Journalism reported that after the Dobbs ruling, Meta "was caught eavesdropping on a period app" through the Facebook SDK embedded in Flo.
Source: TBIJ, September 2025
Privacy policies can be violated. On-device architecture removes the mechanism for violation.
Cited signals
- Flo Health paid a $59.5M combined settlement for sharing reproductive health data without user consent Reuters / FTC, September 2025
- Floriva is a paid app with no free tier, a full-featured on-device option Floriva pricing
Period Tracker App Comparison 2026
| App | Data Architecture | Enforcement History | Platform | Price |
|---|---|---|---|---|
| Floriva | On-device + encrypted sync | None | iOS + Android | Paid app (no free tier) |
| Clue | Server-based (GDPR) | None | iOS + Android | Free / $9.99/mo |
| Euki | On-device | None | iOS + Android | Free |
| Drip | On-device (open source) | None | Android only | Free |
| Natural Cycles | Server-based (FDA-cleared) | None | iOS + Android | $12.99/mo |
| Flo | Server-based | FTC 2021; $59.5M settlement 2025 | iOS + Android | Free / Premium |
| Stardust | Cloud-based | None | iOS + Android | Free |
| Glow | Cloud-based | None | iOS + Android | Free / Premium |
How the options compare, at a glance.
-
Floriva
Paid app (no free tier)
On-device storage with cross-device encrypted sync. iOS and Android. No mandatory account. No third-party advertising SDKs.
Strongest privacy posture with cross-platform support. The only on-device tracker offering encrypted sync across devices.
Pros
- Data stored on-device, no server to subpoena
- Cross-device encrypted sync for users who opt in
- No account required to track
- No third-party advertising SDKs
Cons
- Paid subscription required (no free tier)
- Newer app with smaller prediction dataset than established competitors
-
Clue
Free tier / $9.99/mo
Berlin-based, GDPR-compliant, no advertising business model. Server-based. Scientific advisory board with evidence-based cycle science.
Best privacy among server-based apps. GDPR jurisdiction and no-ads model are real advantages, but server-side data remains accessible via legal process.
Pros
- GDPR compliance under EU law, stronger than US standards
- No ad-funded model
- Scientific advisory board and evidence-based predictions
- iOS and Android
Cons
- Server-based, data exists on Clue's servers and can be subpoenaed
- Requires account
- $9.99/mo for full features
-
Euki
Free
Built by nonprofit Ibis Reproductive Health. On-device storage, no accounts, no data collection. Free. iOS and Android.
Best free on-device tracker. Nonprofit structure and on-device storage together remove both the structural and incentive paths to data monetization.
Pros
- Nonprofit developer with no commercial incentive to monetize data
- On-device storage
- No account or email required
- Free, no ads
Cons
- No cross-device sync
- Fewer prediction and symptom logging features than funded apps
- Less active development
-
Drip
Free
Open source period tracker. Android only. No accounts, no server, no analytics. Source code publicly auditable.
Best for Android users who want verified-not-promised privacy. Open source with on-device storage is the strongest transparency combination available.
Pros
- Open source, privacy claims independently verifiable
- No accounts, no analytics, no server
- Free
Cons
- Android only, no iOS version
- Basic feature set
- No cross-device sync
-
Natural Cycles
$12.99/mo or $99.99/yr
FDA De Novo clearance for contraception (2018). Temperature-based tracking with subscription model. Server-based.
Solid for users prioritizing contraceptive accuracy over privacy architecture. FDA oversight adds accountability, but the server-based model is a privacy trade-off.
Pros
- FDA clearance creates regulatory accountability
- Temperature-based method adds precision beyond calendar prediction
- No documented data-sharing with advertisers
Cons
- Server-based storage
- Most expensive mainstream option at $12.99/mo
- FDA clearance is for efficacy, not privacy
-
Flo
Free tier / Premium subscription
Largest user base. FTC enforcement action in 2021 for sharing data with Facebook and Google. $59.5M combined settlement in 2025. Server-based with paid Anonymous Mode.
The documented enforcement history sets Flo apart from every other app on this list. Anonymous Mode is a policy fix on top of an unchanged cloud architecture. Server-side data remains subpoenable.
Pros
- Large prediction dataset from extensive user base
- Full-featured symptom and cycle tracking
- Anonymous Mode available (paid)
- iOS and Android
Cons
- FTC enforcement action for sharing health data with Facebook and Google (2021)
- $59.5M combined settlement (Flurry $3.5M + Google+Flo $56M)
- Anonymous Mode requires paid subscription, basic privacy costs extra
-
Stardust
Free
Astrology-themed period tracker. Cloud-based. Marketing-level privacy claims without documented technical architecture.
Community features attract users, but unverified privacy claims are not a substitute for documented architecture. No enforcement history, but also no transparency.
Pros
- Free
- Social features and community angle
- iOS and Android
Cons
- Cloud-based with no published privacy architecture details
- Privacy claims are marketing-level, no third-party audit or open source
- No documented on-device storage option
-
Glow
Free tier / Premium subscription
Cloud-based period and fertility tracker with premium features. No documented privacy architecture or third-party audit.
Feature-rich but privacy-opaque. No enforcement history, but no published privacy architecture either. Server-based by default.
Pros
- Full-featured fertility and pregnancy tracking
- Community forums
- iOS and Android
Cons
- Cloud-based, data stored on Glow's servers
- No documented privacy architecture
- Premium features behind paywall
Quick answers to the obvious questions.
Is Floriva good for privacy?
Floriva uses local-first storage. Core cycle data stays on your phone unless optional encrypted sync is enabled. No third-party advertising SDKs. No mandatory account for core tracking. Because Floriva has no readable central cycle database, there is less company-held data to sell or produce.
Is Clue good for privacy?
Floriva is the strongest option because it keeps cycle records off servers entirely. Among server-based apps, Clue is the best fallback. It runs under GDPR, has no advertising business model, and has no documented enforcement actions. But server-based still matters. Data on Clue's servers can be accessed via legal process, which is a real risk for users in US states with abortion restrictions.
Is Euki good for privacy?
Euki is built by nonprofit Ibis Reproductive Health. It uses on-device storage, requires no account, and collects no data. The nonprofit structure removes the commercial reason to sell user data. The trade-off is fewer features and no cross-device sync.
Is Drip good for privacy?
Drip is the most transparent period tracker available. It is open source, uses on-device storage, and has no server, no accounts, and no analytics. Consumer Reports recommended Drip as one of three apps that 'store data locally and don't allow third-party tracking.' It is Android-only with a basic feature set.
Is Natural Cycles good for privacy?
Natural Cycles has no documented data-sharing incidents. FDA clearance is for contraceptive efficacy, not privacy. The app uses server-based storage, so data can be subpoenaed. It is the most expensive mainstream option.
Is Flo good for privacy?
No. Flo is the only app on this list with documented FTC enforcement action for sharing user health data. The FTC found Flo shared period dates, pregnancy status, and symptoms with Facebook and Google without consent. A $59.5M combined settlement followed in 2025. Flo launched Anonymous Mode after the FTC action, but it requires a paid subscription and does not change the server-based architecture.
Is Stardust good for privacy?
Stardust makes marketing-level privacy claims but has not published technical architecture details, open-sourced its code, or completed a documented third-party audit. Cloud-based storage means data sits on Stardust's servers. Privacy claims cannot be independently confirmed without that documentation.
Is Glow good for privacy?
Glow has no documented privacy architecture and no third-party audit. It uses cloud-based storage. No enforcement actions are on record, but without documented architecture users are relying on trust rather than verification.
Questions people ask before they switch.
What is the safest period tracker app in 2026?
On-device trackers are structurally safest because they never transmit data to a server. Among on-device options, Floriva offers the most features with cross-device encrypted sync on iOS and Android. Euki is the best free option. Drip is best for Android users who want open-source transparency.
Which period tracker apps have been investigated by the FTC?
Two period and fertility trackers have faced FTC enforcement action: Flo Health (2021, for sharing reproductive data with Facebook and Google; $59.5M combined settlement in 2025) and Premom (2023, for sharing health data with third-party analytics firms including Chinese companies). Both are server-based apps.
Do I need to pay for a private period tracker?
No. Euki (on-device, nonprofit) and Drip (on-device, open source, Android only) are both free. Floriva is a paid app with no free tier, but it adds cross-device encrypted sync and a fuller feature set. Among server-based apps, Clue offers a free tier under GDPR protections.
Can period tracker data be used against me in court?
Readable data stored on a company's server can be requested through legal process. In states with abortion restrictions, this is a documented risk. The FTC's 2024 research paper found that period tracking app data practices can be used to detect pregnancy and abortion. Local-first trackers reduce this company-side risk because no readable central copy exists.