Screen Resolution Checker

Your screen resolution is shown at the top of the tool card above — for example, 1920 × 1080. This is the size of your screen in CSS pixels, the logical unit browsers use for layout. Below it you will also find the estimated physical resolution, which accounts for display scaling. If the two numbers differ, your display is running with scaling enabled — which is normal and recommended on high-resolution panels. To see the numbers update live, resize the browser window or move it to another monitor.

Modern high-resolution displays use scaling to keep text and icons at a comfortable size. A 4K monitor at 150% scaling reports 2560 × 1440 CSS pixels even though the panel physically renders 3840 × 2160. The browser’s screen.width and screen.height always use CSS pixels, so the reported resolution is the scaled — logical — resolution. Multiply it by the device pixel ratio and you get the physical resolution, which is exactly what the physical resolution estimate on this page does for you.

Device pixel ratio is the number of physical pixels a browser uses to draw one CSS pixel. A DPR of 1 means one CSS pixel equals one physical pixel. A DPR of 2 — common on Retina and modern laptops — means each CSS pixel is drawn with a 2 × 2 block of physical pixels, making content crisper. DPR also changes when you zoom: zooming to 125% in the browser raises the reported DPR by 1.25, which is why the physical resolution estimate is labeled approximate.

Screen resolution describes your entire display — the full monitor or phone screen. The viewport is the visible portion of a web page inside your browser window: it excludes browser toolbars, interface bars, sidebars, and scroll bars. On a maximized browser the viewport is slightly smaller than the screen; on a small floating window it can be much smaller. Web developers use viewport size (not screen resolution) to build responsive layouts, which is why both values are shown side by side on this page.

The physical resolution is calculated by multiplying the CSS resolution by the device pixel ratio and rounding to whole pixels. Two factors make this an estimate: browser zoom changes the reported DPR — at 110% zoom a DPR of 2 is reported as 2.2 — and some browsers apply their own rounding to screen dimensions. The estimate is exact when the browser zoom is at 100%, which is why we recommend checking the value with zoom reset (Ctrl/Cmd + 0) if you need a precise reading.

The available area is the part of the screen that is not occupied by permanent operating system elements such as the Windows taskbar, the macOS Dock, or fixed system bars on mobile devices. A 1920 × 1080 screen with a default Windows taskbar reports an available height of 1040 pixels or less. Applications — including maximized browser windows — are laid out within the available area, so it is often the more practical number when you calculate how much space a maximized window actually gets.

Open this page and read the physical resolution estimate — with browser zoom at 100% it matches the panel’s native resolution, because scaling cannot change how many pixels the hardware renders. You can cross-check in your operating system: on Windows, go to Settings › System › Display and look at Display resolution (the recommended entry is the native one); on macOS, open System Settings › Displays — the "Default for display" option typically uses the native resolution with scaling for sharpness.

Yes. The tool uses only standard browser interfaces, so it runs on Android and iOS browsers as well as desktops. On mobile, the reported screen resolution is usually the device’s logical (CSS) resolution — for example 393 × 851 on many Android phones — while the physical resolution estimate reflects the actual panel. Rotate the device and you will see the orientation, aspect ratio, and both dimensions swap in real time. The available area on mobile excludes system status and navigation bars.

Yes — completely. There is no charge, no sign-up, no download, and no limit on how often you can check. Every measurement happens locally in your browser: the page reads your screen, window, and display settings, and renders them on screen. No screen data, device fingerprint, or usage statistic is sent to any server, and nothing is saved after you close the tab. You can even run it offline once the page has loaded.

The card updates live by design. Resizing the window changes the viewport; zooming changes the device pixel ratio and therefore the physical estimate; rotating a phone swaps width and height; moving the window to a second monitor re-measures the screen it lands on. If numbers changed without any action from you, an external event is responsible — for example a display going to sleep, a docked laptop switching outputs, or an operating system automatically changing scaling for accessibility.