Flo vs Clue vs Glow: Free Period Trackers Compared (2026)
Flo suits you if you want the broadest toolset and an anonymous community, Clue if your cycles are irregular and you want flexible logging, and Glow if you are trying to conceive. They differ most in what costs money and in their privacy records, both checked against each app's own listing and public sources as of October 2026.
Full Transparency
This comparison is published by Holland Neurotech Inc., the company behind Veya. We've mentioned Veya once, where its scope genuinely differs. We've done our best to compare Flo, Clue, and Glow fairly based on each app's published features, pricing, and public record. If Flo, Clue, or Glow is the better fit for you, use it.
Quick Answer
Flo, Clue, and Glow all started as period trackers and grew in different directions. Here's the fast version:
- General period tracking, broadest toolset: Flo. Core cycle tracking is free; per its App Store listing, Secret Chats, the health assistant and in-depth pregnancy features are Premium.
- Irregular cycles, possible PCOS: Clue. Its App Store listing says you can track symptoms even without regular bleeding.
- Trying to conceive: Glow. Its site describes an Ovulation Tracker for people trying to conceive, plus separate Pregnancy and Baby trackers.
Flo, Clue, and Glow all started as period trackers and still come up in "which app should I download" searches. Flo layers fertility, pregnancy and community features onto general cycle tracking. Clue describes a science-first approach with published research collaborations. Glow splits its tools across separate apps, with an Ovulation Tracker aimed at people trying to conceive. The differences that matter most aren't about which has more features. It's what costs money, and which app's design fits what you're tracking for.
The Short Version
If you're in a rush, here's the quick breakdown:
| Flo | Clue | Glow | |
|---|---|---|---|
| Best for | General period tracking | Irregular cycles, PCOS-aware logging | Trying to conceive (TTC) |
| Base | US-based | Berlin, Germany | US-based |
| Free tier | Core cycle tracking | Basic tracking | Separate trackers (check each app) |
| Premium price[1] | up to ~$59.99/yr | $39.99/yr | $59.99/yr |
| Privacy record | FTC order + class action settlement | Mozilla 8/10 (Jul 2026) | 2020 CA AG settlement + 2024 bug |
What Do You Get for Free in Flo, Clue, and Glow?
This is the part most comparisons skim, and it decides whether you're happy with the app you didn't pay for.
Flo's free tier
Per Flo's App Store listing, the app is free to download with core cycle-tracking tools, while Secret Chats, the 24/7 Health Assistant and in-depth pregnancy features are listed as Premium (as of October 2026).[1]
Clue's free tier
Per Clue's App Store listing, Clue is free to download with in-app purchases, and Clue Plus adds deeper analysis, advanced predictions and personalized insights.[2] Some wearable syncing may also need Clue Plus, so check the app for your tier.
Glow's free tier
Glow's site lists four separate apps: an Ovulation Tracker, a Pregnancy Tracker, a Baby Tracker and a Period Tracker (Eve). Glow Premium adds the GlowGPT assistant, advanced analytics, premium articles and ad-free use.[3] Glow's page doesn't say which features in each app are free, so check before you rely on one.
Put plainly: Flo and Clue both keep deeper features behind a subscription, and Glow splits its tools across four apps while listing AI, analytics and ad-free use under Premium.
Flo: What You Get
Flo is a general cycle-health app first, with fertility and pregnancy tracking layered in. Its App Store listing claims over 570 million downloads worldwide (as of July 2026).[1]
Features
- Cycle tracking with AI-powered predictions
- AI Health Assistant that checks in on symptoms like cramps and fatigue (Premium)
- Secret Chats: anonymous community discussions (Premium)
- Pregnancy mode for after conception; in-depth pregnancy features are Premium
Strengths
Community and pregnancy tools. Per its listing, Secret Chats and in-depth pregnancy features are Premium, and the app describes an Anonymous Mode privacy option.[1]
Limitations
Several features, including the AI Health Assistant, sit behind Flo Premium, and its privacy history (below) is worth weighing.
Pricing
Free: Core cycle-tracking tools. Premium adds Secret Chats, the Health Assistant and in-depth pregnancy features.
Flo Premium: App Store purchases are listed up to $59.99 (as of October 2026), with lower-priced tiers also listed.[1]
Download: Available on iOS and Android
Clue: What You Get
Clue was founded in Berlin in 2012 and lists research collaborations on its About page. Its App Store listing says you can track symptoms even without regular bleeding.[2]
Features
- Cycle and symptom tracking with prediction algorithms informed by published research
- Separate tracking modes for Period Tracking, Conceive, Pregnancy, and Perimenopause[2]
- Wearable sync with Apple Watch, Oura, WHOOP, Withings and Fitbit (some syncing may require Clue Plus)
- A minimal interface
Strengths
Built to log irregular cycles. Clue's listing says you can track symptoms even without regular bleeding, and it has separate modes for periods, trying to conceive, pregnancy and perimenopause.[2] Mozilla scored its privacy 8 out of 10 in July 2026, against Flo's 7.[9]
Limitations
Deeper analysis and advanced predictions sit behind Clue Plus.[2]
Pricing
Free: Basic cycle and symptom tracking.
Clue Plus: $39.99/year or $9.99/month on the App Store (as of October 2026).[2]
Download: Available on iOS and Android
Glow: What You Get
Glow's site describes four apps: an Ovulation Tracker for people trying to conceive or wanting to understand their cycle, a Pregnancy Tracker, a Baby Tracker, and a Period Tracker (Eve).[3]
Features
- Ovulation Tracker for cycle and ovulation tracking, including for trying to conceive
- Pregnancy Tracker with due-date calculation and a baby registry
- Baby Tracker for sleep, diapers, and feeding
- GlowGPT health assistant (Premium)
Strengths
Built around trying to conceive. Glow's site describes its Ovulation Tracker for people trying to conceive, with separate Pregnancy and Baby trackers for later stages.[3]
Limitations
Glow has two documented privacy incidents (below): a 2020 California settlement over a consent flaw, and a 2024 bug that exposed profile data. GlowGPT, analytics and ad-free use cost extra with Premium.
Pricing
Free: Glow's page does not spell out which features are free, so check each app.
Glow Premium: $59.99/year after a 7-day free trial (as of October 2026).[3]
Download: Available on iOS and Android
Which Is Right for You: Flo, Clue, or Glow?
What separates these three is which situation each one is built around.
Choose Flo if you're tracking general period health:
- You want a broad toolset and an anonymous community (Secret Chats, Premium)
- You want a general tracker with a pregnancy mode for later
- You're comfortable with Flo's privacy history, or willing to use Anonymous Mode
Choose Clue if your cycles are irregular or PCOS is part of the picture:
- You want to track symptoms even without regular bleeding
- Privacy and a science-first build matter to you
- You plan to bring what you track to a doctor, not rely on the app to diagnose anything
Choose Glow if trying to conceive is why you're tracking:
- You want a tracker aimed at trying to conceive
- You like separate Pregnancy and Baby trackers for later stages
- You've read Glow's current privacy policy and are comfortable with its history
If you actually want your cycle tracked alongside mood, sleep, fitness, and nutrition, that's a different scope than any of the three above. Veya tracks 350+ metrics with cycle data as one part of the picture, free with no ads, though it's iOS only and lacks the community or history these three have built. Worth a look if scope, not a winner, is what you're after.
What Does Each App's Privacy Record Show?
Cycle data is sensitive. Here's the factual record for each app, with dates.
| Privacy dimension | Flo | Clue | Glow |
|---|---|---|---|
| Company base | US-based | Berlin, Germany (EU GDPR) | US-based |
| Regulator / legal action | FTC order 2021 (final June 2021), $59.5M class settlement (final hearing Oct 29, 2026), Meta jury verdict Aug 2025[4][10][6][7] | None that we found | CA AG settlement, 2020[5] |
| Data-exposure incident | Health data shared with Facebook, Google and others, per the FTC | None that we found | API bug, ~25M profiles (not health logs), Feb 2024[8] |
| Anonymized mode | Anonymous Mode described on listing | No | No |
Flo: The FTC announced a proposed settlement with Flo Health on January 13, 2021, alleging it shared health data from millions of users with third parties including Facebook's and Google's analytics divisions, AppsFlyer and Flurry despite privacy promises; the final order was announced June 22, 2021.[4][10] A related $59.5 million class settlement (Google $48 million, Flo $8 million, Flurry $3.5 million) received preliminary approval in April 2026, with a final hearing on October 29, 2026.[6] Meta did not settle: a federal jury found on August 4, 2025 that Meta violated the California Invasion of Privacy Act, with damages to be decided separately.[7] Flo's listing describes an Anonymous Mode.[1]
Clue: Berlin-based; its privacy policy says its data handling meets German and EU legal requirements and that sensitive health data is never shared with or sold to advertisers.[11] We found no FTC order or state settlement for Clue in our checks, and Mozilla scored it 8 out of 10 in July 2026.[9]
Glow: California's Attorney General reached a settlement with Glow, Inc. in September 2020 with a $250,000 civil penalty, alleging that Partner Connect linked accounts without authorization from the user whose data would be shared and that password-change requests were not adequately verified.[5] A TechCrunch report of February 13, 2024 said a bug exposed names, age group, location, user IDs and profile images for around 25 million users, which the researcher said was fixed about a week after reporting.[8]
Mozilla's July 2026 tests scored Clue 8 and Flo 7 out of 10; Glow was not among the apps in the coverage we read.[9] Flo has the longest enforcement history, Glow has two incidents four years apart, and we found none for Clue. None of that makes any one app unsafe, but it's worth knowing.
Frequently Asked Questions
Which is the best free period tracker: Flo, Clue, or Glow?
Flo and Clue both keep deeper features behind a subscription (Flo: Secret Chats, Health Assistant, in-depth pregnancy features; Clue: Clue Plus analysis and predictions). Glow splits its tools across four apps and lists GlowGPT, analytics and ad-free use under Premium.
Is Clue or Flo better for irregular cycles or PCOS?
Clue's App Store listing says you can track symptoms even without regular bleeding, which is why it is a common pick for irregular cycles. Neither app diagnoses PCOS. Bringing what you track to a doctor is the useful next step.
Is Glow good for trying to conceive?
Glow's site describes an Ovulation Tracker for people trying to conceive, plus Pregnancy and Baby trackers for later. Flo and Clue also offer fertility tracking (Clue lists a Conceive mode), but Glow's tools are organized around TTC.
Which app has the strongest privacy record: Flo, Clue, or Glow?
Mozilla's July 2026 testing scored Clue 8 out of 10 and Flo 7; Glow was not in the coverage we read. Flo settled with the FTC in 2021, has a class-action settlement with preliminary approval in April 2026 and a final hearing on October 29, 2026, and Meta lost an August 2025 jury verdict in the same litigation. Glow paid $250,000 to California's AG in 2020, and a 2024 bug exposed profile (not health) data for around 25 million users.
What's a good alternative to Flo, Clue, and Glow?
Veya, if you want cycle tracking folded into a wider health picture. It tracks 350+ metrics across mood, sleep, fitness, and nutrition alongside your cycle, with no ads. Tradeoffs: iOS only, none of the community or track record these three have built.
Weighing two head-to-head instead of all three? See Clue vs Flo, Flo vs Glow, or Flo vs Clue vs Stardust.
References
- Flo Health. App Store listing (in-app purchases, Premium features, download count). apps.apple.com. Fetched October 9, 2026.
- Clue (BioWink GmbH). App Store listing (Clue Plus, modes, wearables). apps.apple.com. Fetched October 9, 2026.
- Glow, Inc. Glow apps and Premium pricing. glowing.com/glow. Fetched October 9, 2026.
- Federal Trade Commission. Developer of Popular Women's Fertility-Tracking App Settles FTC Allegations. ftc.gov, January 13, 2021.
- WilmerHale. California Settles with Glow App Over Alleged Privacy and Security Violations. wilmerhale.com, September 29, 2020.
- HIPAA Journal. Flo Health, Google, and Flurry to Pay $59.5 Million to Settle Privacy Lawsuit. hipaajournal.com. Fetched September 2026.
- PPC Land. Jury finds Meta violated privacy law collecting health data (verdict August 4, 2025). ppc.land. Fetched October 9, 2026.
- TechCrunch. Fertility tracker Glow fixes bug that exposed users' personal data. techcrunch.com, February 13, 2024.
- PPC Land. Mozilla rates Stardust 2 of 10 (also lists Clue 8, Flo 7), summarizing Mozilla's Nothing Personal review of July 16, 2026. ppc.land. Fetched October 9, 2026.
- Federal Trade Commission. FTC Finalizes Order with Flo Health. ftc.gov, June 22, 2021.
- Clue (BioWink GmbH). Privacy Policy. helloclue.com/privacy. Fetched October 9, 2026.
Facts checked against official pages and named sources, October 2026. Prices and policies change, so confirm current terms on each company's site before subscribing.
Try Veya Free
Cycle tracking alongside mood, sleep, fitness, and nutrition in one app. No ads. 1-click logging.
Still deciding between the three above? Track one cycle in whichever app fits your situation and see how it feels.