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Bluemoon vs Flo: catalog facts
Bluemoon	Flo
Best for: People who want a private, simple period tracker on Android	Best for: People tracking their menstrual cycle, ovulation or pregnancy on a phone
Free Free and open source.	Free + paid options Free to download, with a paid premium subscription.
Android	Android, iOS
Data stays on the device Simple interface All 3 strengths for Bluemoon Data stays on the device Simple interface Available on F-Droid and Google Play	Tracks periods, ovulation and pregnancy in one app Symptom logging alongside cycle dates
Android only Focused on basic tracking rather than detailed health insights	Proprietary service that handles sensitive health data Some features require a paid subscription
Downloadable app	Downloadable app, Hosted service
Open source	Not open source
License: GPL-3.0-or-later	License not stated
No account needed	Not stated if an account is needed
Offline features available	Not stated if it works offline
Official website Full listing and sources Sources for Bluemoon nilsgrob.ch/work/bluemoon Catalog checked October 2, 2026	Official website Full listing and sources Sources for Flo flo.health play.google.com/store/apps/details apps.apple.com/us/app/flo-cycle-period-tracker/id1038369065 Catalog checked September 23, 2026

“Not stated” means we have not confirmed it. Features can vary by device and plan.