Track your cycle.
Own your data.
Your Cycle Keeper is a free period and cycle tracker that lives entirely on your device. No servers. No accounts. No ads. Just your health data, encrypted and private.
Stays On Your Device
All data is stored in your browser's local storage. Nothing is ever sent to any server, ever.
PIN Encrypted
Your data is encrypted with AES-256-GCM using your PIN before being written to storage. We hold no keys.
No Account Required
Zero sign-ups. Zero emails. Zero identity. Open the app and start tracking immediately.
Free Forever
No freemium. No premium tier. No subscription. Your Cycle Keeper will always be completely free.
How it works
Simple tracking,
serious privacy
Enter Your Cycle Details
Add the first day of your last period and your average cycle length. No forms, no sign-up, no email required.
Set a Private PIN
Choose a 4-digit PIN that encrypts your data using AES-256-GCM — the same standard used for HTTPS. Only you can unlock your information.
Track Daily Symptoms
Log flow, pain, and mood every day. See your history build into insights — all calculated on your device, privately.
Understand Your Cycle
View your fertile window, predicted ovulation, and cycle patterns on a visual calendar. Know your body better, on your own terms.
Features
Everything you need,
nothing you don't
Cycle Calendar
Visual calendar showing period days, fertile window, and predicted ovulation. Navigate months and log symptoms for any day.
Cycle Insights
Track average cycle length, period duration, fertile window patterns, and symptom trends — all from your own data.
Daily Symptom Logging
Log flow intensity, pain levels, and mood each day. Add free-text notes for anything else you want to track.
AES-256 Encryption
Your data is encrypted with your PIN before being stored, using the Web Crypto API — the same standard used by HTTPS.
Encrypted Backup
Export an encrypted backup file to protect your history. Restore it anytime — on the same device or a new one.
Works on Any Device
Runs in any modern browser on phone, tablet, or desktop. Install as a PWA for an offline app-like experience.
Comparison
Why choose Your Cycle Keeper?
Most period apps make money from your health data. We don't.
| Feature | Your Cycle Keeper | Flo / Clue | Other Free Apps |
|---|---|---|---|
| Completely free | Yes | Freemium | With ads |
| No account required | Yes | No | No |
| Data stays on your device | Yes | No | No |
| No ads | Yes | Paid only | No |
| No data collection or sharing | Yes | No | No |
| AES-256 encrypted storage | Yes | No | No |
| Open source | Yes | No | Rarely |
| Works offline | Yes | Limited | Varies |
FAQ
Common questions
Everything you need to know about privacy, security, and how Your Cycle Keeper works.
Is my data really private?
Yes. Your Cycle Keeper has no server, no backend, and no analytics of any kind. Your data is encrypted with your PIN using AES-256-GCM via the browser's Web Crypto API and stored only in your browser's IndexedDB. We have no ability to access it even if we wanted to.
What happens if I forget my PIN?
For your security, there is no PIN recovery mechanism. If you forget your PIN, the encrypted data cannot be recovered and will be erased. This is intentional — it means no one can access your data without your PIN. We strongly recommend exporting an encrypted backup regularly.
Can I use this on my phone?
Yes. Your Cycle Keeper works in any modern mobile browser. You can also install it as a Progressive Web App (PWA) from your browser's "Add to Home Screen" option for a native app experience that works offline.
How accurate are the predictions?
Predictions are based on the Calendar Rhythm Method using your logged cycle history. They become more accurate as you log more cycles. This is an estimation tool only — not a contraceptive. Stress, illness, and medications can all shift cycle timing.
What if I clear my browser data?
Clearing browser cache is safe. However, clearing "cookies and site data" in your browser settings will erase your cycle data. Always export an encrypted backup before doing so. You can restore it anytime from the Settings screen.
Is this really free forever?
Yes. Your Cycle Keeper is open-source software under the MIT License. There is no premium tier, no subscription, and no ads — ever. Optional donations support development but are never required.
Your health data
deserves to be yours
Free, private, and ready in seconds. No sign-up required.
Open Your Cycle Keeper