Best app for period and ovulation tracking (2026)

Tracking your period and ovulation in one app: what an app can and cannot know, which measurements really help, and how Flo, Clue, Natural Cycles and PERIOD. approach it.

Written by the PERIOD. team. We make a cycle app ourselves. As of October 2026. General information, not medical advice.

Short answer: no app can pinpoint your ovulation from calendar data alone. The best app combines your cycle data with what your body shows, ovulation tests (LH), your basal body temperature and cervical mucus, and shows you a range instead of one "fertile day".

What really helps

• Ovulation tests (LH): a positive test usually means ovulation follows within roughly 24 to 36 hours.
• Basal body temperature: after ovulation your temperature rises by a few tenths of a degree. That confirms afterwards that you ovulated.
• Cervical mucus: clear, stretchy mucus belongs to your fertile days.

How do the apps approach it?

• Natural Cycles works from your temperature (thermometer or wearable) and is the only one of these apps cleared as contraception (naturalcycles.com).
• Clue and Flo predict your fertile days from your cycle data, with extra features in their paid versions.
• PERIOD. predicts your period and fertile window for free. With PERIOD. plus you also log ovulation tests, basal temperature (also from Apple Health) and cervical mucus, so you see what your own cycle does. PERIOD. is not contraception.

Trying to conceive?

Then PERIOD. baby is made for you: from your fertile window to forty weeks of pregnancy and the recovery after. See PERIOD. baby.

For questions about fertility or contraception always talk to your doctor or midwife. Brand names belong to their owners.

Download PERIOD. on the App Store or on Google Play. The basics stay free.