Dead Pixel Test

Dead, stuck or dirt?

The test fills the screen with solid colours. A pixel that is black on every colour is dead. One that shows a single colour, usually red, green or blue, regardless of the background is stuck. A speck that moves when you wipe the screen is dirt; clean before testing.

How to run it

Click Start; the page goes full screen. Click or press any key to step through white, black, red, green, blue and grey. Look at the whole screen for each. Press Esc to finish. Check for backlight bleeding on the black screen in a dark room.

Can it be fixed?

Dead pixels cannot be repaired. Stuck pixels sometimes recover after running a rapidly changing pattern for a while or gentle pressure with a soft cloth, but there is no guarantee. Manufacturers usually replace a new monitor only above a set number of defects; check the policy before buying.

Buying a used screen

Run this test before paying for a used laptop or monitor. It takes a minute and a dead pixel in the centre of the screen is a strong reason to negotiate or walk away.