Screen TestNEW
Find dead pixels and check your display with solid colour grids
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AllFreeTool is a free online screen test that fills the display with solid colours, gradients and grayscale so you can spot dead pixels, stuck pixels and banding, and it reports the screen resolution, the viewport size, the device pixel ratio and the colour depth. A fullscreen pixel test is included for a more thorough check. Everything runs in your browser and nothing is uploaded.
It is useful when you have just bought a monitor or a laptop, when a colleague is about to send you a screen recording and you want to be sure of your own display, or when you notice an odd colour patch and want to work out whether it is the screen or the content. The fullscreen mode hides the page chrome so any irregularity stands out.
Why use Screen Test on AllFreeTool?
Solid Colour Panels
Full-screen pure colours make dead pixels, stuck pixels and uneven backlighting obvious.
Gradient and Grayscale
Gradients and grey ramps reveal banding and issues in the darker and lighter tones.
Screen Details
See the real resolution, the viewport size, the pixel density and the colour depth.
Local Display
The test renders in the page, so nothing about your screen is transmitted.
How to use Screen Test
Enter Fullscreen
Start the fullscreen pixel test to remove the page chrome from view.
Cycle the Panels
Step through the solid colours, the gradients and the grayscale ramps.
Read the Specs
Check the resolution, pixel density and colour depth in the screen information panel.
Common questions
How do I spot a dead pixel?＋
A dead pixel stays black on every panel, and a stuck pixel stays one fixed colour whatever you display. Switch to a solid colour that contrasts with the suspect spot and look for a pixel that refuses to change; if the mark follows you onto the desktop, it is more likely a mark on the panel itself.
Why should I use the fullscreen mode?＋
The page borders and controls can distract from the colours and can hide a fault right at the edge of the display. Fullscreen fills the entire screen with pure colour, which is how a panel is normally inspected, and the exit control brings you back when you are done.
What do resolution and pixel density mean here?＋
The resolution is the native pixel grid of your display, the viewport size is the area the browser can actually draw in, and the device pixel ratio is how many device pixels each CSS pixel covers. A ratio of two is what makes a high-density screen look sharper rather than larger.
Does the test upload anything about my display?＋
No. The colours are drawn by the page and the specifications are read from the browser, so there is no network request at all. Nothing is recorded, and the page works offline on any device that has a screen.