Privacy policy

We do not ask for or store your name, email address, phone number or any account details, because the calculators do not need them.

Every calculation runs in your browser using JavaScript. The dates, cycle lengths and results are never transmitted to our servers, never written to a database, and are gone as soon as you close or reset the page.

We may record anonymous usage events such as which calculator was opened, whether a calculation was completed, and which related link was clicked. These events identify the tool, never the values you entered.

No health-related input is ever included in an analytics event. That restriction is enforced in the code rather than left to convention.

This site is funded by advertising and may display ads served by Google AdSense. Third-party vendors, including Google, use cookies to serve ads based on a user’s prior visits to this or other websites.

Google’s use of advertising cookies enables it and its partners to serve ads based on visits to this and other sites. You can opt out of personalised advertising at Google Ads Settings, or opt out of a third-party vendor’s use of cookies for personalised advertising at aboutads.info.

Advertising partners receive standard request information such as your IP address, browser and the page you are viewing. They never receive the values you enter into a calculator, because those values never leave your browser.

The calculators themselves set no cookies and store nothing on your device. Any cookies present come from advertising partners, and are governed by their own policies.

This site is intended for adults and is not directed at children under 13. We do not knowingly collect information from children.

Depending on where you live, you may have rights to access, correct or delete personal data held about you. Since we do not hold personal data from the calculators, there is generally nothing for us to retrieve or erase. If you believe otherwise, write to us and we will look into it.

Questions go to our contact page.

If this policy changes, the updated version will be posted here with a new date at the top. Material changes to how data is handled will be described rather than quietly edited in.