Dead Pixel Test
Find dead or stuck pixels and backlight bleed with full-screen solid colours and test patterns. Great for checking new monitors, phones and TVs. Free.
Use the colour buttons or arrow keys to cycle through full-screen test colours. Look closely for dots that stay black (dead) or stuck on one colour.
- Dead pixel — stays black on every colour.
- Stuck pixel — stays one fixed colour (often red, green or blue).
- Backlight bleed — uneven brightness, most visible on the black screen.
About Dead Pixel Test
The Dead Pixel Test fills your entire screen with solid colors — red, green, blue, white, black, cyan, magenta, gray and a gradient — so defective pixels have nowhere to hide. A pixel that stays black on every color is dead; one that glows a single fixed color (often pure red, green or blue) is stuck; and uneven brightness around the edges of the black screen is backlight bleed.
Cycling through the full color set matters because each solid color isolates different sub-pixels: a dead red sub-pixel is invisible on blue but obvious on red and white. Use the arrow keys or the on-screen buttons to switch colors, enable auto-cycle to step through them hands-free, and click, tap or press Esc to exit full-screen.
The test is ideal for inspecting a brand-new monitor, laptop, phone or TV while it is still returnable, or for documenting a defect before a warranty claim. It runs entirely in the browser on any device with a screen — nothing is installed and nothing leaves your machine.
How to use Dead Pixel Test
- Clean your screen first so dust specks aren’t mistaken for dead pixels.
- Press Start full-screen test to fill the display with the first color.
- Cycle through red, green, blue, white, black and the other colors with the arrow keys, the buttons or auto-cycle.
- Scan the whole screen slowly on each color, looking for dots that stay black or hold one fixed color.
- Check the black screen for uneven glow along edges and corners — that is backlight bleed.
- Click, tap or press Esc to exit full-screen when you’re done.