A question about Cycle Days (Her Cycle Calendar on the App Store), or something that isn't working? Write to support@edenapps.app. There is no need to include anything about your cycles.
Logging a period
On the Cycle tab, tap Period started on the first day. Tap Period ended on the last day. If you forget, open Calendar and tap the day you meant: you can start, end, or change a period on any day up to today. The day you tap becomes the record, not the day you tapped it on.
Where the expected dates come from
The app takes the middle length of your recent recorded cycles, the median, so one unusual month does not pull the answer around. It counts that many days forward from the first day of your last recorded period, and makes the range as wide as your own cycles vary. Until there are enough cycles it uses the typical length you set, and says so. These dates are an estimate from your own records. They are not a method of birth control and not a medical service, and you should talk to a doctor before making a medical decision.
What is a record and what is an estimate
The calendar draws them differently on purpose. Filled marks are days you recorded. A broken edge is the expected period, which is worked out and can be wrong. This version shows no fertile window and no ovulation estimate.
A cycle that is late or irregular
If the expected range passes with nothing logged, the app says so plainly and leaves it there. If your cycles vary a lot, the range widens and the app tells you why. A gap longer than 90 days is left out of the figures, because a gap that long is usually a stretch that was not recorded.
Locking the app
In More, under Privacy, switch on Lock this app. Face ID, Touch ID, or your device passcode is then checked before the app opens. If the device has nothing to check with, the app opens instead of locking you out of your own records.
Free, and Cycle Days Pro
Logging, the full calendar, the expected dates, the main figures, CSV export, and full backup and restore are free. Cycle Days Pro adds the cycle summary PDF you can hand to a doctor, symptoms you name yourself, the extra insight screens, and the detailed daily fields. It is a one-time purchase.
Keeping a copy, and moving to a new phone
This app's records are left out of your device's iCloud and computer backup, so a lost or replaced phone loses them unless you have a backup file. The app reminds you when the last one is getting old.
In More, choose Back up everything. Save the file somewhere you can reach from the new phone. A computer or a drive of your own keeps it out of iCloud; iCloud Drive works too, but it keeps a copy with Apple. On the new phone, install Cycle Days, open More, and choose Restore a backup. Restoring swaps the history on that phone for the one in the file. The backup is not locked with a password. Anyone who has the file can read your whole history, so keep it somewhere private.
Restoring your purchase
In More, choose Restore Purchases. Pro returns on every iPhone or iPad that uses the same Apple Account you bought it with.
Contact
Write to support@edenapps.app with your question.