Every website can read these values from your browser the moment a page loads, without a permission prompt. Here is what yours reveals, and what each one is used for.
What these values are used for
Languages and time zone let a site pick a locale and, less benignly, confirm whether your claimed location matches your IP. Screen, viewport and pixel ratio drive responsive layouts. Colour scheme and reduced motion are accessibility preferences that well-built sites respect. Hardware details, WebGL renderer and font lists are the raw material of browser fingerprinting, which is why modern browsers round or hide them.
None of this includes your IP address, which is read from the connection rather than the browser; the What Is My IP tool shows that. Your user agent string, decoded, is on the user agent page, and screen details in more depth are on the screen resolution page.
Frequently asked questions
What can a website see about my browser?
Without asking permission: your public IP, user agent, language, time zone, screen and window size, pixel ratio, colour depth, whether cookies are enabled, rough hardware details like CPU core count, and the fonts and features it supports. Together these form a fingerprint that can identify a browser across sites.
Is my time zone a privacy risk?
On its own, mildly. Combined with language and IP location it helps confirm where you really are, which is how some sites detect VPN use when the time zone does not match the IP country.
What is Do Not Track?
A browser header asking sites not to track you. Almost no site honours it and browsers are removing it. Global Privacy Control is its successor.
Why does hardware concurrency show a low number?
Browsers cap or round the reported CPU core count to limit fingerprinting. Firefox and Safari report fewer cores than the machine has.
Does this page store any of this?
No. Everything is read by JavaScript in your browser and shown to you; nothing is sent to our servers.
