About the Screen Resolution Checker
Eight display metrics detected instantly, live-updated on resize and rotate.
What it is
The Screen Resolution Checker reads your display information from browser APIs the moment the page loads — no input needed. It detects eight values simultaneously and updates them live whenever you resize your window or rotate your device.
Everything runs locally in your browser. Nothing is sent to a server, stored, or logged. Close the tab and it's gone.
What it detects
Screen Resolution
The total size of your display in CSS pixels, from screen.width × screen.height. Stays the same when you resize your browser window.
Browser Viewport
The visible area of the web page inside your browser window, from window.innerWidth × innerHeight. Changes as you resize the window.
Actual Pixels
Physical pixel count your browser uses — viewport multiplied by the device pixel ratio. More relevant than CSS pixels for rendering and display quality.
Device Pixel Ratio
How many hardware pixels map to one CSS pixel. Standard displays report 1; Retina and HiDPI displays report 2 or higher, which produces sharper rendering.
Color Depth
Bits per pixel your display supports, from screen.colorDepth. Most modern displays report 24-bit or 30-bit.
Orientation
Whether your device is in portrait or landscape mode, from the Screen Orientation API with a fallback to comparing width and height.
Aspect Ratio
Your screen's width-to-height ratio simplified to its smallest whole-number form (e.g. 1920×1080 → 16:9), computed via the greatest common divisor.
Available Area
The usable screen area excluding OS-reserved space like the taskbar, from screen.availWidth × availHeight.
CSS pixels vs. physical pixels
Modern operating systems let users set a display scale factor (e.g. 150% on Windows, 200% on Mac Retina). This means your browser reports screen dimensions in CSS pixels, which are smaller than your panel's native hardware pixel count. A 4K monitor set to 200% scaling appears as 1920×1080 in CSS pixels, not 3840×2160. The tool reports what your browser sees and clearly labels everything so there's no confusion.
Who it's for
Web designers
Verify viewport breakpoints instantly without digging into DevTools.
Developers
Check DPR and actual pixel counts when building responsive or canvas-based UIs.
Gamers & shoppers
Confirm a display's reported resolution before buying or configuring a game.
Completely free
No sign-up, no rate limits, no premium tier. Open the page and your details appear immediately, on any device.
Check your screen now
Free, no sign-up required. Works on any device.
Open the Screen Resolution Checker