A simple, privacy-focused Progressive Web App (PWA) to track menstrual cycles using the calendar method. All your data stays on your device—nothing is sent to servers.
Calendar Method Tracker is designed to help you track your menstrual cycle and understand your fertility patterns using the calendar method of contraception. The app:
- Logs period start dates - Easily record when each period begins
- Calculates cycle statistics - Automatically computes your average cycle length and identifies patterns
- Works fully offline - Once installed, the app works completely without internet
- Tolerates poor connections - On slow networks (like weak 4G), it automatically falls back to cached data instead of failing
- Privacy-first - All data is stored locally on your device using browser storage; nothing is ever synced to external servers
- Installable - Add it to your home screen on any device (iOS, Android, or desktop)
- Pause tracking - Mark periods as paused if needed (e.g., during medical treatments)
- 📅 Track period start dates with a simple calendar picker
- 📊 View cycle statistics including average cycle length
- 🔒 All data stored locally on your device
- 📱 Works offline with service worker caching
- 🌐 Gracefully handles poor network connections with intelligent fallback
- ⚙️ Pause/resume cycle tracking as needed
- 🎨 Responsive design that works on all screen sizes
- 💾 Data persistence with localStorage
- 🚀 Installable as a PWA on any device