Dead Pixel Test

How do I test for dead pixels?

Run the test above in a dim room and give each color a few seconds. These four steps catch almost every fault.

1. Clean the screen first, so dust is not mistaken for a pixel.
2. Start the test and go full screen, so nothing else is showing.
3. On each color, look across the whole screen, corner to corner. A dead pixel shows as a black dot on the bright colors.
4. Note where any dot is, then check it on every color.

Is it a dead, stuck or hot pixel?

It depends on which colors the dot shows up on. A dot that is black on every color is dead, and one that stays lit is stuck or hot.

A colored dot may only be stuck. Try the stuck pixel test and fixer before you send the screen back.

How do I check a phone or iPhone for dead pixels?

Open this page on the phone, turn the brightness up and start the test. Tap the screen to move to the next color, and hold the phone at reading distance so you can see single pixels.

Browser bars can cover a strip at the top or bottom of a phone screen. To check those edges, rotate the phone, or open a full-screen photo of a solid color from your gallery.

A dead pixel on a phone looks the same as on a monitor: a dot that stays black on every color. A dark patch that spreads from a corner is more often damage than a dead pixel. So is a screen that changes when you press on it.

What does a line of dead pixels mean?

A thin line across the whole screen is a different fault from a dead pixel. A full row or column has failed, which usually points to the panel’s connections or its cable, not to single pixels.

On a laptop, flex the lid gently: if the line flickers or moves, the display cable is the likely cause. You can also plug in an external monitor: if the line shows there too, the fault is in the graphics, not the panel. Lines rarely clear up on their own, and flashing colors will not fix them.

How many dead pixels are acceptable?

That depends on the maker. Most monitor brands publish a pixel policy that sets a limit on bright and dark dots before they will replace a screen. Our dead pixel policy guide compares those limits brand by brand.

Found a dead pixel?

Note where it is and take a photo against a solid color. Then check the seller’s return window and the manufacturer’s pixel policy, which says how many faulty pixels count as a defect. Policies differ by brand, so check before the return window closes.

Our guide to screen returns lists what to keep and what to ask.

Pixels are only one check. Our full screen test also covers backlight bleed, color, refresh rate and touch in about five minutes.