About the dead pixel test
The test cycles a full screen through white, black, red, green and blue. A dead pixel stays black on every field; a stuck pixel stays lit in one colour on every field. Both are only visible against the right background, which is why a single colour is not enough to check.
How to use it
- Go fullscreen and clean the screen first — dust looks exactly like a dead pixel.
- Click or press space to advance through the colours, and look across the whole panel each time.
- A dot that stays black on every colour is dead. A dot that stays coloured is stuck.
Questions
What is the difference between a dead and a stuck pixel?
A dead pixel receives no power and stays black on every colour. A stuck pixel is fixed at one subpixel value, so it shows as a persistent red, green or blue dot. Stuck pixels sometimes recover; dead ones do not.
Can a stuck pixel be fixed?
Sometimes. Rapid colour cycling over the spot for twenty minutes or so occasionally frees it, and gentle pressure on the panel while it cycles helps. Neither is guaranteed.
How many dead pixels justify a warranty claim?
It depends on the manufacturer and the panel class — most set a threshold of several dead pixels, and many exclude single ones entirely. Check your warranty terms.
Does this cost anything or need an account?
No. Every tool on the site is free, needs no sign-up, and works immediately in the browser with nothing to install.
Will my screen stay awake while it runs?
Turn on Keep awake and the browser holds a wake lock, which keeps the display on with no input until you leave the page.
Put this on your site
The embeddable version drops the page around it and runs the tool on its own.