For serious TTC tracking, Fertility Friend wins. It's the most comprehensive charting app with the best ovulation-detection algorithm. For OPK photo tracking specifically, Premom is unmatched. For general cycle awareness with a beautiful UI, Clue is best. Flo is the most popular but the least useful for TTC. Natural Cycles is FDA-cleared but requires a thermometer/wearable and a paid subscription.
Fertility Friend looks like it was designed in 2008 — because it was. But beneath the dated interface is the most powerful fertility charting engine available. It analyzes BBT, OPKs, CM, cervical position, symptoms, and intercourse timing to detect ovulation with remarkable accuracy. Its crosshairs system (solid = confirmed ovulation, dotted = tentative) is the gold standard in the TTC community.
The free version does everything you need. VIP adds chart overlays, pattern analysis across cycles, and early pregnancy sign detection. It syncs with Tempdrop and most BBT thermometers.
✓ Strengths
Best ovulation algorithm available. Handles complex, irregular, and multi-method data. Active community forums. Works with multiple hardware integrations. Minimal data collection.✗ Weaknesses
Ugly interface — looks outdated and cluttered. Steep learning curve for new users. Android app is better than iOS. No OPK photo analysis.Premom's killer feature: photo-based OPK analysis. Snap a picture of your test strip, and the app calculates the test-to-control line ratio, assigns a numerical value, and plots your progression on a chart. Over several days, you can see the LH curve building toward your surge — far more reliable than eyeballing individual strips.
It's made by the same company as Easy@Home test strips, and the two are optimized to work together. Also syncs with the Easy@Home Smart Basal Thermometer for automated BBT charting.
✓ Strengths
Best OPK photo analysis on the market. Clean progression charts. BBT sync with Easy@Home thermometer. Good for visual learners. Free version is feature-rich.✗ Weaknesses
Privacy concerns — past data-sharing controversies. Ovulation algorithm less sophisticated than Fertility Friend. Pushes Easy@Home products (it's a brand app). Limited symptom tracking.Clue is the best-designed period and cycle tracking app, full stop. Clean, gender-neutral interface. Science-backed content. And the strongest privacy stance of any fertility app — based in Berlin, compliant with EU GDPR, and publicly committed to never selling user data.
For TTC specifically, Clue is decent but not great. Its ovulation predictions are calendar-based (using past cycle data), not hormone-data-driven. It doesn't support OPK photo tracking or BBT charting with the same depth as Fertility Friend or Premom. Think of Clue as the best cycle awareness app, not the best TTC app.
✓ Strengths
Best privacy policy of any fertility app. Beautiful, intuitive UI. Gender-neutral language (inclusive). Strong period prediction based on your personal data. Excellent educational content.✗ Weaknesses
Ovulation prediction is calendar-based only. No OPK photo analysis. Limited BBT charting. Not designed with TTC as primary use case. Fertility features behind paywall.Natural Cycles is the only FDA-cleared fertility app. It uses BBT data (from their thermometer, Oura Ring, or Apple Watch) plus a proprietary algorithm to determine your daily fertility status: green (not fertile), red (fertile or uncertain). Its "Plan a Pregnancy" mode specifically identifies your fertile window for TTC.
The catch: it requires a paid subscription and a compatible thermometer or wearable. The algorithm also needs 1–3 cycles to calibrate. For people already invested in the BBT-tracking ecosystem, it's a polished and reliable option. For beginners, the cost-to-start is higher than free alternatives.
✓ Strengths
FDA-cleared algorithm. Clean green/red daily status. Integrates with Apple Watch and Oura. Plan-a-Pregnancy mode is specifically designed for TTC. Good for people who prefer one-tool simplicity.✗ Weaknesses
Expensive subscription. Requires compatible hardware. Algorithm needs 1–3 calibration cycles. No OPK integration. BBT-only — less comprehensive than multi-method approaches.Flo is the most downloaded period tracking app in the world — 380+ million users. It's beautifully designed with a strong content library. For period prediction and general health tracking, it's excellent. For serious TTC, it's one of the weakest options.
Flo's ovulation predictions are entirely calendar-based and assume a standard luteal phase length. It doesn't support OPK photo tracking, doesn't integrate with BBT devices, and its "fertile window" predictions can be off by several days for women with irregular cycles. It also has the worst privacy track record of any major fertility app — it was fined by the FTC in 2021 for sharing health data with Facebook and Google.
✓ Strengths
Huge community. Excellent content library. Beautiful UI. Good for period prediction if cycles are regular. Wide feature set (symptoms, mood, exercise).✗ Weaknesses
Calendar-based ovulation predictions (inaccurate for many). No OPK or BBT integration. FTC privacy violation history. Premium paywall for TTC features. Not designed for serious fertility tracking.📱 Our Recommendation
Use Premom for daily OPK tracking (it's genuinely the best at photo analysis) and Fertility Friend for comprehensive charting (BBT, CM, OPKs, symptoms, intercourse). Yes, using two apps is slightly more work — but each is best-in-class at its specific job. If you want one app only, Fertility Friend handles everything adequately, even if it's not the prettiest.
What About Mira and Inito's Apps?
Both the Mira and Inito fertility monitors have companion apps that are excellent — but they're hardware-dependent. You can't use the Mira app without the Mira device and wands. Same for Inito. If you own the hardware, their apps provide the most data-rich fertility tracking experience available: quantitative hormone levels, AI predictions, and confirmed ovulation. They just aren't standalone apps.
Privacy: The Elephant in the Room
After the Dobbs decision in 2022, fertility app privacy became a genuine concern. Your cycle data can reveal pregnancy, pregnancy loss, and fertility treatment — sensitive information that has legal implications in some jurisdictions.
Clue has the strongest position: EU-based, GDPR-compliant, and has publicly stated it will never comply with US law enforcement requests for user data. Fertility Friend collects minimal data and doesn't sell it. Premom and Flo have the weakest records — both have had data-sharing controversies. Natural Cycles is GDPR-compliant but US-based.
If privacy is your top concern, Clue or Fertility Friend are the safest choices. If you're in a state with restrictive reproductive laws, consider what data you're comfortable sharing with any app.
Start With the Free Tools
Before committing to a paid app or device, try our free ovulation calculator alongside your app of choice.
Ovulation Calculator →