Flo vs Clue vs Glow: Free Period Trackers Compared (2026)
Flo, Clue, and Glow are the three period trackers most people try first, and each one drew a different line between what's free and what costs money. This guide breaks down exactly what you get for free with each app, then looks at which one actually fits your situation: general period tracking, trying to conceive, or cycles that don't run on a predictable schedule.
Full Transparency
This comparison is published by Holland Neurotech Inc., the company behind Go Go Gaia. We've mentioned Go Go Gaia 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, most included free: Flo. Free pregnancy mode, symptom logging, largest community, with ads.
- Irregular cycles, possible PCOS: Clue. Flexible logging that doesn't force a fixed cycle length.
- Trying to conceive: Glow. Built around fertility, with companion apps for pregnancy and baby tracking after.
Flo, Clue, and Glow all launched as period-tracking apps, and all three still come up first in "which app should I download" searches. Flo built out into a full health-content platform with the biggest community in the category. Clue stayed narrower, leaning into a science-first, flexible-logging approach that doctors and privacy advocates tend to respect. Glow built its entire structure, from onboarding to community, around trying to conceive. The differences that matter most aren't about which has more features. It's what you get without paying, 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 | Deepest, with ads | Basic tracking, upsell prompts | Core trackers included |
| Premium price[1] | up to ~$59.99/yr | ~$39.99/yr | ~$59.99/yr |
| Privacy record | FTC settlement + 2026 class action | Clean public record | 2020 CA AG settlement + 2024 bug |
| Community | Largest of the three | Smaller, science-focused | TTC-specific forums |
What Each Free Tier Actually Gives You
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
Flo's free version includes cycle and symptom tracking, a free pregnancy mode with week-by-week updates, and access to Secret Chats, with ads. The AI Health Assistant sits behind Flo Premium.
Clue's free tier
Clue's free tier covers essential cycle statistics and basic predictions, with account creation at no cost.[2] Pregnancy mode, wearable sync, and deeper pattern analysis require Clue Plus, with periodic upgrade prompts on the free tier.
Glow's free tier
Glow's free tier is broader than it looks: Period, Ovulation, Pregnancy, and Baby trackers are all included at no cost.[3] Glow Premium adds unlimited GlowGPT, health forecasting, and an ad-free experience.
Put plainly: Flo's free tier wins on pregnancy mode, though it runs ads. Clue's free tier is thinner but flexible by design. Glow's free tier already covers fertility, pregnancy, and baby tracking, saving AI features for Premium.
Flo: What You Get
Flo is the most-used period tracker in the category, with a user base in the tens of millions. It's built as a general cycle-health app first, with fertility and pregnancy tracking layered in.
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
- Pregnancy mode with week-by-week tracking, included free
Strengths
The largest community, plus a free pregnancy mode. Secret Chats put you in anonymous discussions on nearly any cycle topic, and week-by-week pregnancy tracking is included free.
Limitations
Free users see ads, and the AI Health Assistant sits behind Flo Premium. Flo doesn't offer nutrition or sleep tracking, and its privacy history (below) is worth weighing.
Pricing
Free: Cycle and symptom tracking, pregnancy mode, community access. Includes ads.
Flo Premium: up to ~$59.99/year at time of writing (September 2026), with lower-priced monthly and multi-month tiers also listed in-app.[1]
Download: Available on iOS and Android
Clue: What You Get
Clue was founded in Berlin and built its identity around a science-first approach to cycle tracking, leaning on published research partnerships and EU data rules. It's also genuinely good at handling cycles that don't run on a fixed schedule.
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 (Oura, Fitbit, WHOOP) and Clue Connect sharing, both with Clue Plus
- A clean, minimal interface with no ads
Strengths
Genuinely good with irregular cycles. Clue doesn't force a rigid 28-day model onto your data, and the app adjusts to a long, short, or unpredictable cycle rather than flagging it as wrong, which is part of why PCOS-related irregularity tends to fit better here. It also carries the strongest privacy reputation of the three.
Limitations
The free tier is thinner than Flo's or Glow's, with pregnancy mode and wearable sync behind Clue Plus and periodic upgrade prompts. Clue also has a smaller community than Flo, with no dedicated TTC community.
Pricing
Free: Basic cycle and symptom tracking.
Clue Plus: ~$39.99/year at time of writing (September 2026).
Download: Available on iOS and Android
Glow: What You Get
Glow was built from the start as a fertility and TTC app, encouraging users to log more detailed inputs than a typical period tracker, then expanding into a family of apps: Glow Nurture for pregnancy, Glow Baby for after birth, and Eve by Glow as a more casual cycle-tracking sibling.
Features
- Cycle and fertility-window tracking built around conception
- Detailed logging inputs: basal body temperature, cervical mucus, ovulation test results
- Community forums organized around TTC and pregnancy loss
- Companion apps for pregnancy (Glow Nurture) and baby tracking (Glow Baby)
Strengths
Built for TTC specifically, not retrofitted onto a general tracker. The logging, insights, and community are all organized around trying to conceive, and its Period, Ovulation, Pregnancy, and Baby trackers are all free, with premium reserved for AI features and forecasting.[3]
Limitations
Glow has two documented privacy incidents (below): a 2020 California settlement over a consent flaw, and a 2024 bug that briefly exposed profile data. Its detailed logging can also feel like a lot if you're not deep into a TTC protocol.
Pricing
Free: Period Tracker, Ovulation Tracker, Pregnancy Tracker, and Baby Tracker.
Glow Premium: ~$59.99/year at time of writing (September 2026), with a free trial offered before billing starts.[3]
Download: Available on iOS and Android
Which One Fits Your Situation
What separates these three is which situation each one is built around.
Choose Flo if you're tracking general period health:
- You want the deepest free tier and the largest community
- You want a free pregnancy mode without paying
- 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 logging that doesn't assume a fixed cycle length
- 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 detailed logging inputs like temperature and cervical mucus
- A TTC-specific community matters to you
- 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. Go Go Gaia 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.
Privacy: What Each App's Record Shows
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 2021, $59.5M class action (final hearing Oct 2026), Meta jury verdict Aug 2025[4][6][7] | None on record | CA AG settlement, 2020[5] |
| Data-exposure incident | Health data shared with Facebook, Google, pre-2021 | None on record | API bug, ~25M profiles (not health logs), Feb 2024[8] |
| Anonymized mode | Yes, Anonymous Mode | No | No |
Flo: FTC settled with Flo Health in January 2021 over sharing health data with Facebook, Google, and others.[4] A related class action got preliminary approval in April 2026 for a $59.5 million settlement (final hearing October 29, 2026),[6] and a jury found Meta liable in August 2025.[7] Flo has since added Anonymous Mode.
Clue: Berlin-based, governed by strict EU GDPR rules, with no FTC action, state settlement, or class action on record.[2]
Glow: California's AG settled with Glow, Inc. in September 2020 over a Partner Connect flaw sharing reproductive health data without consent, a $250,000 penalty.[5] A February 2024 API bug exposed profile data, not health entries, for roughly 25 million users, fixed within a week.[8]
Clue has the cleanest record, Flo has the most enforcement history balanced against real remediation, and Glow has two incidents four years apart, both addressed. 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's free tier includes pregnancy mode and community, with ads. Clue's is basic, saving pregnancy mode for Clue Plus. Glow's covers period, ovulation, pregnancy, and baby trackers, saving AI for Premium. Flo goes furthest for pregnancy tracking.
Is Clue or Flo better for irregular cycles or PCOS?
Clue tends to fit better, since it doesn't force a rigid 28-day model onto data that runs long or unpredictably. Neither app diagnoses PCOS. Bringing what you track to a doctor is the useful next step.
Is Glow good for trying to conceive?
Yes, that's what it's built for: fertility-window tracking, detailed logging, and companion apps for pregnancy (Glow Nurture) and baby tracking (Glow Baby) once you conceive. Flo and Clue support fertility tracking too, but Glow's whole structure is organized around TTC.
Which app has the strongest privacy record: Flo, Clue, or Glow?
Clue, by a wide margin: Berlin-based, GDPR-governed, nothing on record. Flo settled with the FTC in 2021, has a class-action settlement that got preliminary approval in April 2026 with a final hearing on October 29, 2026, and lost a 2025 jury verdict against Meta, though it's since added Anonymous Mode. Glow paid $250,000 to California's AG in 2020, and a 2024 bug briefly exposed profile (not health) data for around 25 million users.
What's a good alternative to Flo, Clue, and Glow?
Go Go Gaia, 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 in-app pricing tiers. App Store listing. Fetched September 2026.
- Clue (BioWink GmbH). Free vs. Clue Plus features, EU data privacy standards. helloclue.com. Fetched September 2026.
- Glow, Inc. Free tracker features, Glow Premium pricing. glowing.com/glow. Fetched September 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.
- CNBC. Jury rules Meta violated law in period-tracking app data case. cnbc.com, August 7, 2025.
- TechCrunch. Fertility tracker Glow fixes bug that exposed users' personal data. techcrunch.com, February 13, 2024.
Facts checked against official pages and named sources, September 2026. Prices and policies change, so confirm current terms on each company's site before subscribing.
Try Go Go Gaia 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.