Privacy

Privacy policy

Last updated: October 30, 2026. The calculator is designed to process dates locally in your browser.

Calculator inputs

Dates, cycle settings and the irregular-cycle option are used by JavaScript in your browser to calculate results. The calculator does not require an account and does not send those inputs to our server.

Website requests

Your browser and hosting provider may process ordinary technical information needed to deliver pages, such as an IP address, request time and user agent. Your browser and hosting provider may process ordinary technical information needed to deliver pages. If you install the site, its service worker may cache site files on your device so previously opened pages can work offline.

Cookies and local storage

The site does not use cookies. If you choose “Remember my details on this device” in the calculator, your last-period date, cycle settings and irregular-cycle choice are stored only in this browser’s localStorage. They are never sent to our server. The theme preference is also stored locally. Use “Forget my data” in the calculator or clear this site’s browser data to remove saved values. Anyone using the same device and browser may be able to see saved values.

Contact email

If you email us, your message and address are handled by your email provider so we can respond. Please do not send sensitive health information. Contact the site team only for website feedback.

Changes

We may update this policy when the site changes. The date above indicates the latest revision.