No fertility app can accurately predict ovulation from period dates alone. Apps become useful when you log biological data (OPKs, BBT, cervical mucus). Premom is best for OPK-based tracking (reads strip photos). Fertility Friend is the gold standard for BBT charting. Natural Cycles is the only FDA-cleared app but requires a thermometer. Flo and Clue are good period trackers but weak ovulation predictors without manual data.
Head-to-Head Comparison
| App | Free Version | Paid Price | OPK Integration | BBT Charting | Best For |
|---|---|---|---|---|---|
| Premom | Yes (full-featured) | $30–$50/year (premium) | Yes — reads strip photos via camera | Basic | OPK users who want photo analysis and trend tracking |
| Fertility Friend | Yes (comprehensive) | $45/year (VIP) | Manual logging | Excellent — the most detailed charting | BBT enthusiasts and data lovers; best chart interpretation |
| Natural Cycles | Limited free | $100/year + thermometer | No native integration | Yes (core feature) | Women wanting FDA-cleared algorithm; good for BBT-only tracking |
| Flo | Yes | $50/year (premium) | Manual logging | Basic | Period tracking and general health; large community; weak on ovulation prediction |
| Clue | Yes | $30–$50/year | Manual logging | Basic | Clean interface; science-forward; better for cycle awareness than TTC optimization |
| Ovia Fertility | Yes (full-featured) | Free | Manual logging | Manual logging | Completely free; decent prediction when you log multiple signals |
| Read Your Body | Yes | $12/year | Yes | Yes | FAM practitioners; extremely customizable; handles multiple signs well |
Data privacy warning
Fertility apps collect extremely sensitive health data. After the Dobbs decision in 2022, concerns about law enforcement accessing period tracking data intensified. Clue stores data in Germany (under EU GDPR protections). Natural Cycles is based in Sweden. Flo settled with the FTC in 2021 over sharing user data with Facebook and Google, and subsequently introduced an “Anonymous Mode.” Read privacy policies before logging sensitive health information.
Build Your Complete Tracking System
Apps work best combined with physical tools. Our comparison covers OPKs, monitors, and thermometers.
Read the Full Tracking Guide