Dead Pixel Test
This page starts automatically cycling through white, black, red, green, and blue — the fastest way to check a monitor, laptop, or phone screen for dead and stuck pixels without clicking anything. Tap Fullscreen for the clearest results.
How this dead pixel test works
Why cycle through five colors instead of just one
A dead pixel always looks black, so it's easy to miss on a black screen but obvious on white or a bright color. A stuck pixel is the opposite — it stays one fixed color, so it's easiest to catch against a background of a different color, or against black. Cycling through white, black, red, green, and blue in sequence catches both failure types, since every pixel gets checked against a background it should visibly contrast with.
How long should I run the test for
A full pass through all five colors, done slowly and carefully, is usually enough — there's no benefit to running it for a long time once you've inspected the whole screen against each color. If you're checking a used device before buying, a 2–3 minute careful look, ideally at a slower cycle speed (5+ seconds per color) with the screen in fullscreen, is generally sufficient.
What counts as a "pass"
If you don't see any small dot that stays the same color while the background changes around it, and you don't see obvious backlight bleed on the black screen or dull/uneven patches on the white screen, the panel is in good shape. A single dead or stuck pixel is common enough on budget panels that many manufacturers explicitly allow a small number under warranty — check the seller's dead-pixel policy if you find one before deciding whether to return the device.