Privacy

The calculators

Both calculators do their arithmetic in your browser. The dates and birthday you enter are not transmitted anywhere, not written to storage, and are gone when you close the tab.

The personal day calculator asks for a birth month and day. It does not ask for a birth year, because the calculation does not use one. Collecting a full date of birth for no reason would be worse for you and no better for the result.

What is kept on your device

Two small values are saved in your browser’s local storage: your visit streak, and which version of a call-to-action you were shown so it stays consistent between visits. Both stay on your device, are never sent anywhere, and clearing your browser data removes them.

Working out which day you are on

Midnight happens at different moments around the world, so to show you the right date the site needs a rough idea of where you are. When you open the home page, the network your request arrives on reports an approximate timezone, and you are forwarded to that day’s page.

That check happens in transit and nothing about it is stored. No location, no timezone and no address is written to a database, kept in your browser, or attached to anything else you do here — the site has no account to attach it to. The only lasting effect is which date’s page you land on.

Analytics

This site uses Google Analytics, deliberately set up so that it stores nothing on your device. No cookies are set, and your IP address is anonymised before it is recorded. It counts page views and a handful of interactions, such as which links get used and which version of a button you saw.

Because nothing is stored in your browser, you are not recognised as the same visitor if you come back later. That makes the visitor numbers less accurate, which is the trade being made on purpose. The measurements are processed by Google on this site’s behalf.

The same counts are also sent to PostHog, a product analytics service, processing them on this site’s behalf in the European Union. It is configured the same way: nothing is written to your device, so you are a new visitor every time, and session recording is switched off, so no replay of what you did on the page is ever captured.

Either way, no cookie is set for tracking purposes, which is why you have not been asked to dismiss a consent banner.

Error reports

When something on the page breaks, a report is sent to Sentry so it can be fixed. It contains what went wrong and where in the code — the error message, the page it happened on and the browser version. It is set up not to attach your IP address, and nothing you type into a calculator is included, because none of that leaves your device in the first place. These reports are processed in the European Union.

Affiliate links

Some links go to other companies’ sites and carry a tag showing the visit came from here. Once you follow one, you are on their site under their privacy policy, not this one. Which links those are, and what this site earns, is set out on the disclosure page.

Hosting

Pages are served as static files from a content delivery network. Like any web server, the host records standard request information such as IP address and user agent in order to serve the page and defend against abuse.