Screen & Dead Pixel Test
Full-screen colours to find dead pixels and backlight faults.
Screen Test fills your display with solid colours, gradients and test patterns in full screen so you can spot dead or stuck pixels, backlight bleed, uniformity problems and colour banding. It also reports your resolution, pixel ratio, colour gamut and refresh rate.
Loading Screen & Dead Pixel Test…
Runs entirely on your device. No file or text you enter here is uploaded. How to verify it.
How to use Screen & Dead Pixel Test
- Read the reported resolution, pixel ratio and gamut.
- Enter full screen and cycle through the colour fields.
- Look for pixels that stay the wrong colour, and for uneven backlighting.
Questions about Screen & Dead Pixel Test
Dead pixel or stuck pixel?
A dead pixel stays black on every colour because its transistor has failed and is generally permanent. A stuck pixel shows one fixed colour — red, green or blue — because a subpixel is held on, and can sometimes be freed by the flashing pattern included here.
What is backlight bleed?
Light escaping around the edges of an LCD panel, most visible on a full black screen in a dark room. A small amount is normal on IPS displays; large bright patches are a defect worth a warranty claim.
What does the gamut reading mean?
Whether your display reports support for sRGB, Display P3 or Rec.2020, via CSS media queries. It reflects what the browser is told, which is usually right but depends on the operating system profile.
Does it work on a phone or tablet screen?
Yes. The colour fields fill a mobile screen well enough to find a dark blotch, a stuck subpixel or OLED burn-in. True full screen is restricted on iOS, so scroll once to hide the browser bars before judging the edges of the panel.
What should I check when buying a used monitor?
Run the black field for dead pixels and backlight bleed, the white field for dust and uneven brightness, and the red, green and blue fields for stuck subpixels, which hide on white. Finish with the gradient to look for banding. A minute on each field catches almost anything worth rejecting the screen over.
Is Screen & Dead Pixel Test really free, with no limits?
Yes. There is no account, no daily cap, no file-size tier and no watermark, because there is no server cost to recover. The site is funded by clearly disclosed partner recommendations on the Partners page, never by metering the tools.
Are my files or text uploaded when I use Screen & Dead Pixel Test?
No. Everything is processed by JavaScript running in your browser, on your device. You can verify it: open your browser's developer tools, switch to the Network tab, and use the tool. You will see no request carrying your data — because there is nowhere for it to go.