Dead Pixel Test
Cycle fullscreen colors to spot dead or stuck pixels in under a minute.
The screen goes fullscreen and cycles white → black → red → green → blue. Click or press any key for the next color. Press Esc to exit at any time. Look closely for dots that don't match the rest of the screen.
How this test works
Every pixel on an LCD or OLED panel is made of red, green, and blue sub-pixels. Showing a solid fullscreen color drives every sub-pixel of that color to maximum, which makes failures obvious: a dead pixel stays black on the white screen, and a stuck sub-pixel glows as a colored dot on the black screen. Cycling through white, black, red, green, and blue isolates each sub-pixel type in turn, so a single pass catches both dead and stuck pixels anywhere on the panel.
The test uses your browser's Fullscreen API so the color truly covers the whole panel, including the taskbar and browser chrome. Nothing is measured automatically — panel defects are physical, so your eyes are the instrument. Sit close, and scan the screen in a grid pattern on each color.
Found a bad pixel? What to do next
Confirm it's the panel, not dirt
Wipe the spot gently with a microfiber cloth. Dust and dried droplets mimic dark pixels on light backgrounds. A real pixel defect stays in exactly the same position on every background color and doesn't move when you change resolution.
Stuck (colored) pixel
A pixel stuck on red, green, or blue sometimes recovers. Leave the display running on changing content for a few hours, or re-run this test and let it sit on each color for a minute. Some stuck pixels return to normal after a power cycle: turn the monitor off, unplug it for a few minutes, and try again. Gentle massage of the spot through a soft cloth is a widely reported fix, but do it at your own risk — pressing hard can damage the panel.
Dead (black) pixel
A pixel that stays black on white, red, green, and blue is dead, and software cannot revive it. Your options are warranty service or acceptance. Check the manufacturer's pixel policy: many define how many defects qualify for replacement, and premium lines often have zero-defect guarantees within the first year. Laptop panels follow the laptop maker's policy, not the panel maker's.
Windows 11 and macOS notes
Run the test at the display's native resolution (Windows: Settings → System → Display; macOS: System Settings → Displays) — non-native scaling can blur a single-pixel defect into invisibility or create false ones. If you use display scaling or HDR, the colors will still render fully, so results are unaffected.
Frequently asked questions
What is the difference between a dead pixel and a stuck pixel?
A dead pixel gets no power and stays black on every color, so it shows up best on the white screen. A stuck pixel is locked to one sub-pixel color — a red, green, or blue dot that stands out on the black screen and on the solid color screens.
Can a stuck pixel be fixed?
Sometimes. Stuck pixels occasionally recover on their own or after gently cycling colors in that area for a few minutes. Dead pixels are hardware failures and cannot be fixed by software.
How many dead pixels count as a warranty defect?
It varies by manufacturer. Many follow ISO 9241-307 class definitions, where a small number of defects is considered acceptable, but several brands offer zero-bright-pixel guarantees on premium monitors. Check your monitor's pixel policy before filing a claim — and use this test's result line as your report.
Why do I see a faint dark smudge instead of a single dot?
That is more likely dirt on the screen or backlight bleed / a panel defect rather than a single dead pixel. Wipe the screen first; if the mark stays in the exact same spot on every color, it is in the panel.