How to check for dead pixels
- Turn screen brightness to maximum and wipe the screen with a dry cloth — dust looks like a dot.
- Tap Start dead pixel test. The screen fills with black, white, red, green, blue and grey.
- On each colour, look slowly across the whole screen, corners included.
- A dot that stays the same on every colour is a faulty pixel.
Dead pixel vs stuck pixel
Dead pixel — always black, most visible on the white screen. It gets no power and usually can't be fixed at home.
Stuck pixel — always red, green, blue or white, most visible on black. One sub-pixel is stuck "on". Stuck pixels sometimes recover by themselves after a few days.
When to worry
One pixel on a new phone is often within the maker's tolerance, but many shops accept returns in the first 14 days — test a new or second-hand phone right away. A growing group of dots, lines or colour patches usually means display damage; a service centre can confirm it.
FAQ
Does this test work on iPhone and Android?
Yes. It runs in any browser — Safari, Chrome, Samsung Internet. On iPhone add the page to the home screen for true full screen.
Can I fix a dead pixel?
A truly dead (black) pixel can't be fixed by software. Stuck colour pixels sometimes come back on their own.
Is one dead pixel normal?
On cheaper panels one pixel is often tolerated by the warranty. Check your seller's return policy.
Does it work on laptops and monitors?
Yes. Open the page on the device and press the button — it goes full screen.