Device Info
Reading…
Nothing here is sent anywhere
Every value is read from your own browser and rendered locally. The page makes no network requests, which is worth knowing given this is exactly the data fingerprinting scripts collect.
Device info shows fifteen values your browser makes available to any page you visit: viewport and screen size, pixel ratio, platform, languages, time zone, CPU cores, memory and more. It is useful for debugging a layout, and it is also a demonstration of how much a page learns about you without asking.
How it works
Every value is read from standard browser APIs. Screen, navigator, matchMedia and Intl. None requires permission, and a page can read all of them silently on load.
- Viewport is the space your page actually has; screen is the whole display. They differ by browser chrome, which is why layouts break when tested against the wrong one.
- Device pixel ratio is how many physical pixels make one CSS pixel. 2 or 3 on modern phones, 1 on older desktop monitors.
- Device memory is deliberately rounded to a power of two, and CPU core count may be capped, specifically to reduce fingerprinting precision.
- Reduced motion and colour scheme are the accessibility preferences your CSS should already be respecting.
Taken together these values are a fingerprint. Individually each is unremarkable; combined, the set is often unique enough to identify a returning visitor without any cookie.
Examples
Viewport against screen
Device
A laptop with a 1440p display
Result
Screen 2560 × 1440, viewport 1280 × 620
The gap is browser chrome and the operating system scaling factor. Media queries respond to the viewport, so testing against screen size gives the wrong answer.
A phone
Device
A modern smartphone
Result
Device pixel ratio 3, touch points 5
A pixel ratio of 3 means images need three times the CSS dimensions to look sharp. Touch points above zero is the reliable way to detect a touch device.
Frequently asked questions
Is any of this information sent anywhere?
No. Every value is read from your own browser and rendered locally, and the page makes no network requests. That is worth stating plainly given the page exists partly to show what a site can silently collect.
Why does device memory show a rounded number?
Because the specification requires it. The value is rounded to a power of two and capped at 8 GB precisely so it cannot be used as a precise fingerprinting signal. Several browsers do not report it at all.
What is the difference between viewport and screen size?
Viewport is the area your page can draw in; screen is the whole display including everything the browser and operating system occupy. CSS media queries respond to the viewport, which is why a layout tested against screen dimensions breaks in a real window.
Can a site identify me from these values?
Often, yes. Individually each value is common, but the combination of screen size, time zone, language list, core count and platform is frequently unique enough to recognise a returning visitor with no cookie at all. That is what browser fingerprinting means.