A private period tracker that never leaves your phone

MoonDot logs your cycle and predicts what's coming next using only your own averages, stored only on your device. No account, no cloud, no one else in the room.

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The problem

The average period app wants an email, a login and a home in the cloud. That means the most intimate data you keep — when you bleed, when you're fertile, when you're late — sits on someone else's server, folded into a privacy policy almost no one reads. In a time when people have real reason to worry about who could request, share or sell reproductive-health data, "trust us" is no longer a comfortable answer. You shouldn't have to hand your cycle to a company just to find out when your next period is likely to arrive.

How MoonDot (Period Tracker) works

• Tap the days your period starts and ends, and add symptoms whenever you want the fuller picture.
• MoonDot reads your own history and estimates your next period, ovulation and fertile window from your personal averages — not a one-size-fits-all 28-day guess.
• Everything shows up on a simple calendar you can scroll back through anytime.
• Because there is no account to create, you are logging within seconds of opening the app.

What you get

• Cycle logging and calendarMark period days and symptoms and see your whole history laid out on a clean, scrollable calendar. Free, with no limits.
• Predictions from your own averagesNext-period, ovulation and fertile-window estimates are calculated from the cycles you have actually recorded, so they grow truer to you over time.
• No account, everThere is no sign-up, no email and no password to forget. Open MoonDot and start — that is the whole setup.
• Calendar reminders (.ics)One tap adds your next predicted period to Apple, Google or Outlook calendar, with a heads-up 2 days before. The file is created on your phone; when the prediction moves, MoonDot tells you to update it. Free.
• PIN lock, charts and a doctor report (Pro)For a one-time US$1: a PIN so the app opens only for you, cycle charts and symptom patterns, full history, CSV export and a report you can print or save as a PDF for your next appointment.

Private by design

MoonDot runs entirely on your device. There is no account, no login and no cloud sync — your logs are written to your phone and stay there. Nothing about your cycle, your symptoms or your fertile window is uploaded, because there is no server to upload it to and no company inbox it could land in. We cannot read your data, sell it or be asked to hand it over, for the simple reason that we never receive it in the first place.

Free vs Pro

What's new

v1.1 · 2026-09-25

• Add to calendar: one tap saves your next predicted period as an .ics event with a reminder 2 days before — made on your phone, no account, no server
• The reminder on the day asks whether your period started, so logging day 1 stays one tap; the Today card nudges you when it's due or late
• Discreet mode: calendar events can show only “🌙 MoonDot” if your calendar is shared or synced
• Pro: a doctor report you can print or save as a PDF — cycles, lengths, symptoms and notes on one page
• Every sentence now reads naturally in all 15 languages, and fonts are bundled so the app makes no font requests at all