Birthday Math

Privacy Policy

Last updated September 29, 2026

Votes

If you answer "Do you know someone born on…?", we store your answers anonymously, together with the date and a scrambled code made from your IP address. We never store the IP address itself, and the code can't be turned back into it. We use it only to allow one vote per birthday and to stop automated voting. Your browser also remembers that you voted on that date, so the button can say "Update my vote". Clearing your browser data removes that.

Your birthday calendar

If you create a birthday calendar, we store your email address and the birthdays you add (names, dates, the year if you give it and who they are to you). We use them only to show you your calendar, to send you sign-in links and to build your private calendar link. We don't send newsletters, and we never sell or share your list. Sign-in emails are sent through SendGrid. Anyone who has your private calendar link can see your list, so keep it to yourself, and you can replace it with a new one at any time. You can delete your account, and every birthday in it, from your calendar page whenever you like.

Analytics

We use StatCounter to count page views. It records standard information such as the page visited, the referring page, browser type and an approximate location derived from your IP address. We use it only to see which pages are read. StatCounter's own policy is at statcounter.com.

Server logs

Like any website, our server keeps standard access logs (IP address, time, page requested and browser). They are used for security and troubleshooting and are deleted on a rolling basis.

Cookies and advertising

The site does not run advertising and does not set its own tracking cookies. If you sign in to your birthday calendar, we set one cookie that keeps you signed in for up to 180 days. Signing out removes it.

Changes

If this policy changes, the date at the top of this page will change with it.