Peridot - Period Calendar

A simple period tracker that does exactly what you need — and everything is free.

Peridot is a clean period calendar for logging your period, seeing your next predicted date, and moving on with your day. No accounts, no articles, no forums, no pink glitter. Just the basics, done well.

ALL FEATURES FREE
Period prediction, ovulation and fertile window, PMS days, home screen widget, reminders, statistics, themes, export — nothing is locked behind a paywall. No subscription, no one-time purchase, nothing to unlock.

WHY PERIDOT

• Log in two taps — open the calendar, tap the day, done
• See days until your next period at a glance, right on the home screen widget
• Period predictions that adapt to your recent cycles, not just averages
• Ovulation, fertile window and PMS days marked clearly on the calendar
• Late? The counter shows exactly how many days past your predicted date
• Track flow, symptoms, mood, notes and pill intake — only if you want to
• Gentle reminders before your predicted date, plus an optional pill reminder
• Cycle statistics: average cycle length, period length, and history
• Light and dark mode with a calm, neutral design — not a pink app
• Discreet look: nothing on the icon or widget gives away what the app is

YOUR DATA STAYS YOURS
Peridot works completely offline. Your records are stored only on your phone — no account, no server, no cloud. Deleting the app deletes your data. Use JSON export whenever you want your own backup file.

LIGHT AND FAST
Peridot is a small native app. It opens instantly, works offline, and won't drain your battery.

A NOTE ON PREDICTIONS
Period and ovulation predictions in this period tracker are calendar-based estimates for personal reference only. They are not medical advice and should not be used for diagnosis, treatment, or as a contraception method.

Whether you switched from a bloated period tracker app, want a simple menstrual cycle calendar for predictions, or just need a period calendar that respects your privacy — Peridot keeps your cycle organized without getting in the way.