Question 1

How do I test my monitor for dead pixels?

Accepted Answer

Open the tool, click Fullscreen, then step through each solid color (red, green, blue, white, black). A dead pixel shows as a permanent black dot on every color; a stuck pixel stays a fixed color (often red, green or blue) no matter the background. A bright always-on sub-pixel is stuck, not dead.

Question 2

What is the difference between a dead pixel and a stuck pixel?

Accepted Answer

A dead pixel is permanently off (black) because it receives no power — it usually cannot be fixed. A stuck pixel is lit in one color and can sometimes be recovered by flashing rapidly changing colors (there are dedicated stuck-pixel fixer videos). This tool helps you spot both.

Question 3

Why test with multiple solid colors?

Accepted Answer

Each sub-pixel (red, green, blue) is tested against its own pure color. A stuck blue sub-pixel is invisible on a blue screen but glows on red or green. White reveals any dark (dead) pixels, while black reveals stuck-on pixels and backlight bleed.

Question 4

Does this tool work on phones and tablets?

Accepted Answer

Yes. It runs in any modern browser with Fullscreen API support. On mobile, tap a color to go fullscreen and swipe or tap to switch. Everything is processed locally — no images are downloaded and nothing is uploaded.