Dead pixel test

How to check for dead pixels

1. Clean the screen gently so dust is not mistaken for a pixel.
2. Start the test to fill the screen with a solid colour.
3. Tap, click or press the arrow keys to move through each colour, looking closely.
4. Press Esc or tap exit to leave full screen.

Dead, stuck and hot pixels

Each pixel on your screen is made of tiny red, green and blue parts. When one goes wrong, it shows up as a dot that does not match the colour around it:

• Dead pixel: always black, easiest to see on the white screen
• Stuck pixel: always one colour, such as red, green or blue; it shows up on the colours it does not match
• Hot pixel: always white or bright, easiest to see on the black screen

That is why the test runs through several colours. A pixel stuck on green blends in on the green screen but stands out on black, red and blue.

How to look properly

Wipe the screen with a dry microfibre cloth first, as a speck of dust looks a lot like a dead pixel. Dim the room if you can. On each colour, scan the screen slowly in sections, top left to bottom right, from about the distance you normally sit. Then look closer at anything suspicious. If a dot moves when you wipe the screen, it was dust.

Check the edges and corners too, which are easy to skip. On a phone, turn the brightness up, as some faults are easier to see.

What to do if you find one

Test as soon as a new screen, laptop or phone arrives. If you bought it from a shop or online in the UK, the Consumer Rights Act gives you 30 days to reject a faulty item for a refund. Many retailers also have their own returns window, which can be easier to use.

After that, it depends on the manufacturer. Many have a pixel policy that only counts a screen as faulty once it has a certain number of bad pixels, or one in the centre. Policies vary a lot between brands, so check yours before contacting them. Take a photo of the pixel on the test colour, as it helps with any claim.

Questions people ask