Smart predictions. Complete privacy. Zero tracking.
All your data stays on your device.
Your data never leaves your device. No servers, no tracking, no sharing.
Everything stays on your device. We literally can't access your data.
No analytics, no cookies, no fingerprinting. Period.
Download your data as JSON or CSV whenever you want.
Start tracking instantly. No email, no password, nothing.
Everything you need to track your cycle with confidence
Learns your patterns and predicts your next period with confidence scores.
Visualize trends and compare your cycles to medical averages.
Log symptoms, mood, and flow. See patterns over time.
No app store needed. Works on iPhone, Android, and desktop.
Eye-friendly dark theme with automatic switching.
Switch from any app with CSV import or manual entry.
Track, predict, understand
Tap any day to mark period start and end. Add symptoms anytime.
Algorithm learns your patterns and predicts your next period and fertile window.
View charts, patterns, and trends. Compare with medical averages.
Click on a day to see how tracking works
See how easy it is to log periods, symptoms, and view predictions
Ready to start tracking your real cycle?
Open CycleSyncNo app store required - install directly from your browser
Navigate to cyclesync.net/app in Safari browser
Tap the share icon at the bottom
Select "Add to Home Screen" and tap "Add"
Navigate to cyclesync.net/app in Chrome browser
Tap the three-dot menu in the top right
Select "Install app" or "Add to Home screen"
Absolutely. CycleSync stores all your data locally on your device using IndexedDB. We have no servers, no databases, and no way to access your information. Your data never leaves your device unless you explicitly export it.
Yes! CycleSync is a Progressive Web App (PWA) that works completely offline. Once installed, you can track your cycle anywhere, anytime, with or without internet connection.
CycleSync uses a weighted algorithm that adapts to your unique patterns. The more cycles you track, the more accurate predictions become. We show confidence levels with each prediction, so you always know how reliable the forecast is. Our algorithm is specifically designed to handle irregular cycles.
Yes! CycleSync supports CSV imports from popular apps like Clue, Flo, and others. We also provide a guided import wizard and instructions for requesting your data from other apps via GDPR/CCPA.
Yes, CycleSync is completely free with all features unlocked. No subscriptions, no in-app purchases, no ads. Privacy-first period tracking should be accessible to everyone.
Since data is stored locally, you'll need to export from your old device and import on the new one. Simply go to Settings > Export Data to download a backup file, then import it on your new device. This gives you complete control over your data migration.
Absolutely! Our weighted prediction algorithm is specifically designed to handle irregular cycles. It gives more weight to recent cycles and adapts to your changing patterns, providing realistic predictions with confidence levels.
Start tracking your cycle with complete privacy and confidence.
Open CycleSyncNo signup required • Works on all devices • 100% free