Contact
- Email: iuliana.iagodka@gmail.com
- GitHub issues: IulianaIagodka/Rhythma
Please include your iOS version, Rhythma build number (Settings), and a short description of what happened.
What Rhythma is
Log the first day of your period, see recorded and forecasted days on week and year calendars, and optionally use calendar sync and phase-based load advice.
It is not a fertility, ovulation, or medical app. Predictions are estimates only and must not be used as contraception.
Free
- Record your period from Today, or confirm a date on the year calendar
- Week and year calendars for recorded and forecasted period days
- Today cards: cycle status, this week, selected day, and phase context
- Phase name on Today: Menstrual, Follicular, Ovulatory, Luteal phase
- Predicted cycle day and ovulation labels on forecast dates
- Calendar sync — connect your iPhone calendar to see events alongside your cycle
- Optional ovulation marks (off by default)
- Light or dark appearance
- English and Ukrainian, based on the iPhone language
Rhythma Plus
The first logged cycle includes Plus features free. After that, a monthly or yearly subscription unlocks Cycle insight (phase and hormones), Schedule insight (plan and activity fit with Calendar sync), and Energy curve. Payment is via Apple ID. Restore purchase is available in Settings. Cancel in iPhone Settings → Apple ID → Subscriptions.
Privacy (including purchases): Privacy Policy. Terms of Use: Apple Standard EULA.
How to use
- Open Today and log the first day of your period, or tap a day on the year calendar and confirm.
- Use week and year views for recorded days and the period forecast.
- In Settings, choose appearance, forecast, and optional ovulation marks.
- Turn on Calendar sync in Settings and allow calendar access when iOS asks.
- To remove a logged day, tap it again on the year calendar and confirm.
Google Calendar
Rhythma does not sign in to Google and does not connect to Google Calendar directly. It reads events from calendars already added on this iPhone.
- iPhone Settings → Calendar → Accounts (on newer iOS: Settings → Apps → Calendar → Calendar Accounts).
- Add Account → Google, then sign in.
- Turn Calendars on for that account.
- Open the Calendar app → Calendars → check the Google calendars you want.
- In Rhythma → Settings, turn on Calendar sync and allow Full Access.
iOS calls this “Full Access” because it does not provide a read-only Calendar permission. Rhythma only reads events to show them in the app. It does not create, edit, or delete your calendar events.
The same steps work for iCloud, Outlook, or any other account in the iPhone Calendar.
Troubleshooting
Calendar events do not appear. Turn on Calendar sync in Settings and allow Full Access. Events show on their start day. To see Google Calendar events in Rhythma, first add the Google account to the iPhone Calendar.
Why Full Access for a cycle tracker? iOS calls this “Full Access” because it does not provide a read-only Calendar permission. Rhythma only reads events to show them in the app. It does not create, edit, or delete your calendar events.
The cycle length looks wrong. Estimates come from the days you have logged. Log a few more periods and the forecast updates.
Wrong language. Rhythma follows the iPhone language (English or Ukrainian). Change it in iOS Settings → Rhythma, or in the iPhone language settings.
I deleted the app. Cycle data lives only on this iPhone. Deleting the app deletes that data. There is no Rhythma account or cloud backup.
Privacy
Your cycle data stays on this iPhone. Rhythma does not create an account and does not upload cycle data to a server.
Calendar access is used only when you turn on Calendar sync. iOS calls this “Full Access” because it does not provide a read-only Calendar permission. Rhythma only reads events to show them in the app. It does not create, edit, or delete your calendar events.
Plus subscriptions are billed by Apple; Rhythma does not collect payment card details. Full policy (including purchases): Privacy Policy. Terms: Apple Standard EULA.
Sources
Rhythma explains how estimates are made and links to published references (PubMed, NCBI Bookshelf, ACOG). No purchase is required.
In the app: Settings → Sources & Methodology. Small ⓘ icons on estimates open the relevant section.
Disclaimer
Rhythma provides cycle estimates for personal planning. It is not medical advice, a diagnostic tool, or a fertility or contraception product. If you have health questions, talk to a clinician.