Cyclical

Cyclical is a clean, lightweight biorhythm chart for your phone.

Enter your birth date once and the chart is yours. No account to create, no login screen, no daily prompts to dismiss. Tap any column for that day's exact cycle values, swipe to navigate dates, and add a second birth date to compare two people's charts side-by-side.

No account. No ads. No tracking SDKs. Your birth date stays on your device.

— What you get —

• Six cycles drawn as sine waves: four classical (intuitive, emotional, intellectual, physical) plus two longer observational cycles. Show or hide each independently.
• A 15, 30, or 56-day chart you can scroll through any day.
• Daily moon phase emojis in every column, oriented for the Northern or Southern Hemisphere using your device time zone.
• Critical-day markers showing the moments each cycle crosses zero.
• A Circle View that shows today's cycles as a single ring of dots — handy for spotting when several rhythms cluster together.
• Person comparison: enter a second birth date to see two charts at once.
• A home-screen widget with today's rhythms at a glance, so you don't need to open the app to check.
• Dark and light themes; default is dark.

— What it isn't —

Cyclical is a personal-curiosity chart. Biorhythms are a long-running cultural curiosity — the cycles are computed from your birth date as a fixed mathematical pattern, not measured from anything happening in your body. We make no claim that any cycle predicts how you'll feel or perform. Cyclical is not a substitute for advice from a professional.

— Privacy —

The app itself doesn't require an account, name, or email address — your birth date stays on your device. If you choose to contact support, the optional form on the Support page asks for your name and email so we can reply. The only network call the app makes is to fetch moon-phase data for the dates on your chart; that request carries the date you're viewing and your IP address (the same way any HTTP request does) and nothing about you. You can delete everything the app holds at any time by clearing app data or uninstalling.

The full privacy policy lives at https://cyclical.info/privacy/

— Built for —

Anyone who likes the idea of a sine-wave chart matched to the calendar, who wants moon-phase visibility alongside it, and who'd rather not hand over personal data to use a small reference app.