Screen Resolution Checker

What this tool does

The Screen Resolution Checker reads and displays the measurements your browser knows about your display and window. In one glance you get the full screen resolution, the available screen area, the current browser viewport size, the device pixel ratio, the colour depth, the orientation, and the effective physical resolution. The viewport-related numbers update live as you resize the window or rotate a device, so the page always reflects the current state rather than a stale snapshot.

It loads instantly with real values — there is no button to press and nothing to configure. Each value has a copy button, and a Copy all button produces a tidy plain-text report you can paste into a bug ticket, a support chat or a design note.

When you would use it

The most common reason is troubleshooting. A web page looks broken, an image is blurry, or a layout that works on a colleague’s machine misbehaves on yours — the first useful question is “what resolution and pixel ratio are you actually running?” This tool answers that in seconds, without digging through operating-system settings menus.

Designers and front-end developers use it to confirm the device pixel ratio before exporting assets: a 1× export looks soft on a 2× or 3× screen, so knowing the DPR tells you which resolution of an image to ship. QA testers paste the Copy all report into bug reports so a developer can reproduce the exact display conditions. People buying or selling a used laptop or monitor use it to verify that a screen really runs at the resolution advertised. And anyone setting up a screen share or recording can check the viewport size to be sure the captured area is the size they expect.

How to use it

1. Open the page. All values are read and shown straight away — no setup.
2. Read the cards. Each one shows a measurement with a short explanation of what it means.
3. To watch values update, resize the browser window: the viewport size, device pixel ratio and orientation refresh live. On a phone or tablet, rotate the device and the orientation row flips.
4. Click the small copy icon on any card to copy that single value, or use Copy all to copy the whole report as plain text.

How to read the results

Screen resolution is your display’s total size in CSS pixels. Available screen area subtracts space taken by the taskbar, dock or menu bar — it is the room a maximised browser window can occupy. Viewport size is the live size of the area inside this browser window. Device pixel ratio tells you how many physical pixels make one CSS pixel: 1 is a standard display, 2 or 3 is a high-density screen. Effective physical resolution multiplies the screen resolution by the DPR to estimate the panel’s real pixel grid. Colour depth is the bits used per pixel, normally 24-bit. Orientation reports landscape or portrait.

If a number looks wrong, the fix lives in your operating system’s display settings, not in the browser — this tool only reports. A blurry site on a high-DPR screen usually means the site shipped low-resolution images, which is the site’s problem, not yours.

Browser compatibility

Every value here comes from long-standing, well-supported web APIs, so the tool works in all modern browsers on desktop and mobile — Chrome, Edge, Firefox, Safari and Opera. The screen.orientation API is the only newer piece; where a browser lacks it, the tool falls back to comparing width and height and still reports landscape or portrait correctly.

To see what else your browser exposes, try the Browser Info Viewer. For battery details use the Battery Status Checker, to test your camera use the Webcam Test, and to check location access see the Geolocation tool.

Privacy

Everything in this tool happens inside your browser. The measurements are read locally and shown back to you; nothing is uploaded, saved or logged, and closing the tab discards it all.