Free hardware tester
Screen Resolution Test: Size and Pixel Ratio
Runs locally in your browser. Nothing is uploaded.
Screen resolution test
Read the browser-reported screen, viewport, pixel ratio, color depth, and orientation.
Last updated: July 29, 2026
Screen resolution test: This screen resolution test reads the dimensions and display properties exposed to the browser without requesting permission.
How this screen resolution test works
Read the CSS screen size and device pixel ratio, then compare the estimated device-pixel dimensions with operating-system display settings. Resize the browser to see the viewport update separately.
How to read the results
Screen size describes the browser’s CSS coordinate space. Device pixel ratio maps CSS pixels to device pixels. Operating-system scaling can make their product differ from the panel’s marketed native resolution.
Common causes of failed tests
Unexpected values can come from scaling, zoom, remote desktop, mirroring, browser privacy reduction, rotation, virtual displays, or the browser sitting on another monitor.
Troubleshooting before you replace hardware
Reset browser zoom, confirm advanced display settings, move the browser to the intended screen, and compare the monitor’s on-screen information. Use the value as browser context, not hardware certification.
For setup and buying context, see the screen test hub, color screens, and refresh rate test.
Frequently asked questions
Why is the reported resolution smaller than native?
Operating-system scaling can expose a smaller CSS coordinate space.
What is device pixel ratio?
It is the number of device pixels represented by one CSS pixel along each dimension.
Does this reveal physical screen inches?
No. Browsers do not reliably expose physical panel dimensions.