About the Dead Pixel Test
This dead pixel test fills the whole screen with one solid color at a time so you can find dead, stuck and hot pixels and backlight bleed by eye. A tiny faulty dot is easy to miss in everyday use, but on a plain colored screen it stands out immediately.
Run it as soon as you unpack a new monitor, laptop or phone, and before buying a used device. Most retailers only accept returns for pixel defects within a short return window.
How to use
- Press Start full-screen test. On a phone, turn the brightness all the way up.
- Close the info box, then tap, click or press โ to step through the colors while you scan every corner of the screen.
- If one dot looks different from the rest, note where it is. A photo helps if you file a return or warranty claim.
- Press Esc or Quit on the last screen to finish.
Types of pixel defects
| Defect | What it looks like | Best color to spot it |
|---|---|---|
| Dead pixel | Always off, a black dot | White |
| Hot pixel | Always on, a bright dot | Black |
| Stuck pixel | Stuck on red, green or blue | Black, white and each primary color |
| Backlight bleed | Cloudy light at the edges (LCD) | Black, in a dark room |
| Burn-in / mura | Ghost images or patchy brightness (OLED) | Gray |
If you find a bad pixel
- Dead pixel policies vary by manufacturer. Many monitors are only replaced once a certain number of defects is reached, so check whether your model has a zero-dead-pixel guarantee.
- Test right after delivery: store return windows (often 14โ30 days) are usually easier than a warranty claim.
- A stuck pixel sometimes recovers after a video of rapidly changing colors runs for 10โ30 minutes. A dead pixel that is completely off usually cannot be fixed.
FAQ
Full screen doesnโt work on my iPhone.
Safari on iPhone does not let web pages enter full screen, so the address bar may stay visible. Rotate to landscape or scroll to shrink the bar, and turn the phone to check the area it covers.
Is that a speck of dust or a dead pixel?
Wipe the screen with a soft cloth and look again. If the dot stays in the same spot with the same shape on every color, it is a pixel defect; if it moves or wipes away, it was dust.
Can I check an OLED screen for burn-in?
Yes. On the gray and white screens, look for faint outlines of the status bar, navigation bar or keyboard. Maximum brightness makes burn-in easier to see.
Can this test damage my screen?
No. It only displays solid colors. On OLED screens, just close the test when you are done so the same image isnโt left on for a long time.