Current Phase

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Cycle Day

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Until Next

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Avg Length

Day 1Day 28

Period

Fertile

Ovulation

Luteal

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Cycle Stats

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Avg Length

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Avg Period

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Cycles Logged

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Fertile Days

Symptom Tracking

Period Ovulation Flow Pain Mood

How it Works

Your Cycle Keeper estimates your fertile window by tracking cycle patterns. Ovulation is estimated ~14 days before your next period. Fertile days are calculated as day 8 through (cycle length − 11).

For regular 28-day cycles, this means days 8–17 are typically fertile, with ovulation around day 14.

⚠️ This is an estimation tool only. Not for contraception. Stress, illness & medications can shift timing.

Cycle History

No history yet.

Short (<26d) Normal (26–32d) Long (>32d)

About Your Cycle Keeper

Your Cycle Keeper is free software built with care for privacy. Based on the Calendar Rhythm Method and Standard Days Method for cycle estimation. For informational purposes only.

Version: 1.0.0-beta
License: GNU General Public License v3.0
Developer: pythonime-lab

Found a bug or have a suggestion? Visit our GitHub repository.

Support Development

Your Cycle Keeper is free forever with no ads, no tracking, and no data collection. If you find it helpful and would like to support continued development, you can buy me a coffee!

Support via

Your support helps keep this project maintained and ad-free for everyone. Thank you! 💜

Privacy Guarantee

Your Cycle Keeper collects zero data. This app:
• Stores all data locally on your device only
• Has no servers, no accounts, no cloud storage
• Has no analytics, no tracking, no telemetry
• Has no ads, no third-party code
• Never transmits any data anywhere
• Is encrypted with your PIN via AES-256-GCM

Your health data is yours alone.

Medical Disclaimer

⚠️ This app provides cycle estimations based on average biological patterns. It is not medical advice and must not be used as a substitute for professional medical consultation.

Your Cycle Keeper predicts your cycle by tracking patterns and estimating ovulation timing. Actual cycle timing can vary due to stress, illness, medications, and many other factors.

Do not use this app as a contraceptive or fertility guarantee. Always consult a qualified healthcare professional for medical decisions.

Accessibility

Your Cycle Keeper follows WCAG 2.0 accessibility standards:

• Tab/Shift+Tab: Navigate forward/backward through all interactive elements
• Arrow Keys: Navigate calendar dates (complex grid component)
• Enter/Space: Activate buttons and links
• Escape: Close modals and return focus to trigger element
• PIN Entry: Type digits 0-9 and Backspace on all PIN screens
• Form Controls: Native keyboard support for inputs, selects, and textareas
• Screen Readers: Semantic HTML with proper ARIA labels and roles
• Focus Management: Visible focus indicators, logical tab order

Standards based on Salesforce Accessibility Guidelines.

Cycle Settings

Last period start date

Average cycle length (days)

Period duration (days)

Language

Security & Privacy

AES-256-GCM Encrypted

All data is encrypted with your PIN before being stored. Cycle Keeper uses the Web Crypto API — the same standard used by browsers for HTTPS.

Zero data is sent to any server. No accounts. No analytics.

Storage used: Calculating...

⚠️ Data Persistence: Your data is stored in IndexedDB. Clearing browser cache is safe, but clearing "site data" or "cookies and site data" in your browser settings WILL erase all your cycle data. Always export a backup first!