How to use it
- Nothing to enter: every value is detected when the page opens.
- The tiles give the browser and version, the engine, the OS, screen resolution and window size, pixel density, language, time zone and the rest.
- The window size updates by itself as you resize the browser window.
- The Copy the summary button collects everything into text, handy to attach to a support request.
Where the values come from
Everything on this page is what the browser reports about itself through standard interfaces: the User-Agent string (browser, version, engine, OS), the screen object (display resolution), window (window size and pixel density) and Intl (language and time zone). Any site you open receives the same data; this page only shows it to you in readable form.
How accurate the browser, version and OS are
- The browser name and version are parsed out of the User-Agent string. Usually accurate, but the string can be spoofed in settings or by an extension.
- The operating system version is deliberately coarse in current browsers: recent macOS releases all report themselves as 10_15, and Windows 10 and 11 are indistinguishable. That is anti-tracking behaviour, not a fault of this tool.
- Screen resolution is given in CSS pixels, with the physical resolution next to it once density (devicePixelRatio) is taken into account — that second figure is the real number of dots on the panel.
It is all computed on your side
The tool sends none of this to a server: the User-Agent string, the screen dimensions and every other value are read and displayed in the browser. Copy the summary simply puts them as text on your clipboard, and where you paste it is up to you.
Questions
What browser am I using?
The one shown in the first tile and in large type at the top: the tool parses the name and version out of your User-Agent string. The engine and operating system are there too. It is all detected on the page, with nothing sent to a server.
Why is the operating system version imprecise?
Current browsers deliberately blur the OS version in the User-Agent so that you are harder to track by a unique set of parameters. That is why recent macOS releases look like 10_15 and Windows 10 and 11 cannot be told apart — browser behaviour, not an error.
Does any of this get sent anywhere?
No. Every value is read and shown in the browser, and nothing reaches affpapa.org. The Copy the summary button puts the text on your clipboard and nowhere else.
What are devicePixelRatio and physical pixels?
devicePixelRatio is how many physical dots of the display there are per logical CSS pixel. On Retina and similar screens it is 2 or more, so the physical resolution is the screen dimensions multiplied by that number.
Why is the window smaller than the screen resolution?
Screen resolution covers the whole display, while the window size (innerWidth by innerHeight) is only the visible area of the tab, without browser chrome or scrollbars. So the window is almost always smaller, and it changes as you drag the window edges.
