A small flashing square you drag over a stuck pixel, with a seizure warning first
Processed in your browser. Nothing is uploaded. Updated on 24 Oct 2026.A stuck pixel shows one fixed colour, red, green, blue or white, and sometimes frees itself when the colours under it change quickly for a while. Drag the small flashing square over it and leave it for 10 to 20 minutes. Read the photosensitivity warning first. A dead pixel, one that stays black on every colour, cannot be brought back this way, and a stuck one is not guaranteed either.
Read the Photosensitivity warning first; do not use the flasher if flashing light affects you.
Pick Slow or Fast for the flash speed, and tick I have read the warning and want to start the flashing square.
Press Start the flashing square and drag the square over the stuck pixel.
Leave it flashing for several minutes, then press Exit and check the pixel on the colour test.
This page fills your whole screen with one solid colour at a time: black, white, red, green, blue and mid grey. A pixel that is not doing what its neighbours are doing is easy to see against a flat colour and nearly impossible to see in a photo or a web page. The test uses the browser's full-screen mode where it is allowed, and fills the window where it is not, as on an iPhone.
Every pixel is three sub-pixels, red, green and blue. A dead pixel never lights, so it shows as a black dot on white. A stuck pixel has a sub-pixel that is always on, so it shows as a bright red, green or blue dot on black. A sub-pixel that is stuck off shows as a dark dot on its own colour, which is why the three primaries are in the list. Mid grey is for the panel as a whole: patches that are lighter or darker than the rest are uneven backlight, and light creeping in from the edges on black is backlight bleed.
A stuck pixel sometimes frees itself when the colours under it change quickly for a while. The flasher is a 96 pixel square you drag over the pixel and leave for 10 to 20 minutes. Flashing can trigger seizures, so the page warns first and needs you to confirm, and when your system asks for reduced motion only the slow speed is offered. The square cannot revive a dead pixel, and it does not promise to fix a stuck one.
The rest of the article, and all 6 questions about Dead Pixel Test, are on the Dead Pixel Test page.
A dead pixel never lights at all, so it shows as a black dot on a white screen. A stuck pixel has one of its red, green or blue parts permanently on, so it shows as a bright coloured dot on black. Stuck pixels sometimes recover; dead ones almost never do.
Clean the screen, dim the room and press start. Step through black, white, red, green, blue and grey, and scan each colour in sections from your normal viewing distance. Anything that stays the same on every colour is probably dust or a scratch rather than a pixel.
Sometimes. Rapidly changing colours under a stuck pixel can free it, so drag the square over the spot and leave it running for 10 to 20 minutes. Nothing can promise a fix, and a dead pixel that stays black on every colour will not come back this way.
No. Flashing light can trigger seizures in people with photosensitive epilepsy, which is why the page shows a warning and asks you to confirm before it starts. The square is kept small, and the slow speed changes colour only twice a second, but anyone at risk should not use the flasher.
Still stuck? Ask about Dead Pixel Test and anybody who knows can answer. No account needed.
On the related tools: CPS Test 10 Seconds – A 10 second clicks-per-second test, long enough to show whether your speed holds · Countdown Timer – Set minutes and seconds, or tap a preset, and hear an alarm when time is up.