Meet Cylune, a calm and private period calendar designed around one simple question: when is your next period likely to begin?

Cylune is completely free, with no ads, subscriptions, in-app purchases, accounts, or paid features. It works offline and requires no external service. Created with enduring care for women and deep respect for their privacy.

View and edit every period in one calm calendar: tap a day to select it and tap again to remove it. One missing day remains part of the same period; longer gaps create separate periods automatically.

PRIVATE BY DESIGN

• No account or sign-in
• No advertising or tracking
• No analytics SDKs
• No cloud database
• No internet permission
• Cycle entries remain in private app storage

SIMPLE CYCLE AWARENESS

• Edit, add, or remove any period day in one fast calendar
• Adjust period length and rhythm when needed
• See missing days predicted from the first selected day
• Let an active period complete elapsed days automatically when you forget
• Hold or double-tap any day to add, edit, or delete a private comment
• See the next likely start and date window
• See the current period day or estimated fertility likelihood
• Review confirmed and estimated entries separately
• Correct or delete accidental entries from history
• Fill an empty month in one tap, or confirm six-month prefill at the end of history
• Pause automatic periods during an editable pregnancy range, defaulting to nine months
• Reopen directly in your last selected Extended or Simple view
• Understand the learned average and prediction confidence
• Keep missed estimates current automatically

Cylune is intended for personal organization and cycle awareness. All predictions are estimates. Cylune is not a medical device and must not be used for contraception, diagnosis, or treatment. Consult a qualified healthcare professional about medical concerns.