See your screen size, pixel ratio, viewport and colour depth, with a summary you can copy.
Your screen resolution is the width and height your browser reports for the screen, shown at the top of the page, for example 1920 × 1080. It is measured in CSS pixels, the units web pages are laid out in, not always in the physical dots on the panel. The browser reads it from screen.width and screen.height. On a laptop with a sharp display and operating system scaling, the CSS size is often smaller than the native resolution. A screen that reports 1440 × 900 CSS pixels with a device pixel ratio of 2 has about 2880 × 1800 device pixels.
The device pixel ratio says how many device pixels cover one CSS pixel in each direction. A ratio of 1 means one to one. A ratio of 2 means each CSS pixel is a 2 by 2 block of device pixels, which is how many phones and sharp laptop screens look crisp. Estimated physical pixels is the screen width and height times that ratio, rounded: 1920 × 1080 at a ratio of 1.25 gives 2400 × 1350. It is an estimate. Operating system scaling, such as 125% or 150%, feeds into the ratio, and so does browser zoom on a desktop, where zooming to 200% reports a ratio of 2 on a screen that is really at 1. Set zoom to 100% to read it.
Screen is the whole display. Available screen is the part left once the operating system takes its bars, such as a taskbar or the macOS menu bar, so its height is often a little smaller. Browser viewport is the area inside the browser that this page can use, and it is the only value that follows your browser: it changes live when you resize the browser, open the developer tools or zoom, and it is the size a responsive page designs for. Colour depth is the bits per pixel the browser reports, commonly 24. Orientation says landscape or portrait and, where the browser gives it, the rotation angle. Touch points is the number of fingers the device can report at once, and 0 on most computers without a touch screen.
It cannot read the screen size in inches, the refresh rate or the panel type, because browsers do not expose them. With several monitors it reports the one the browser is on. Some browsers round or limit these values to reduce tracking, and a phone may report a size that is not its native resolution. Missing values show as Not reported. Nothing you see is saved or sent, and the page counts visits with Google Analytics, never your screen size. Copy summary puts all the values on the clipboard as plain text.
It is the big number at the top of this page, such as 1920 × 1080, width by height in CSS pixels. Below it you will find the device pixel ratio and the estimated physical pixels, which are the real dots on a sharp screen.
Operating system scaling. A 3840 × 2160 panel set to 200% reports 1920 × 1080 CSS pixels with a device pixel ratio of 2. Estimated physical pixels multiplies the two back to 3840 × 2160.
Screen is the whole display, for example 1920 × 1080. The viewport is the area inside the browser that the page can use, such as 1280 × 720 in a smaller browser. Only the viewport changes when you resize the browser.
On a desktop, browser zoom works by changing the ratio. At 200% zoom a screen that was at a ratio of 1 reports 2. The screen size row does not change. Reset zoom to 100% to read the true ratio.
No. Browsers do not report the physical size of a screen or its refresh rate. You can work out the diagonal in inches from the product specification, not from the pixel count.
No. The values are read by your browser in this tab and shown to you, and no server receives them. The page counts visits with Google Analytics, never your screen size.