See the screen size, browser viewport, device pixel ratio, estimated device pixels, color depth, and orientation reported by your browser.
Measurements update when the window or display orientation changes, making it easy to compare CSS pixels with the device-pixel estimate used by the current browser.
Screen and viewport sizes are reported in CSS pixels. The screen size describes the browser's view of the display, while the viewport is the usable area inside the current browser window.
The device-pixel estimate multiplies the reported screen size by the device pixel ratio. It can help explain why screenshots and canvas output contain more pixels than the CSS dimensions suggest.
Browser zoom, operating-system scaling, external displays, and privacy protections can change or reduce the reported values, so the estimate is informative rather than a hardware specification.