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Dead pixel test

Press Start to go full screen. Scan slowly across each color for any dot that does not match.

More device tests

Kinds of pixel defects

  • Dead pixel: always off, so it shows as a black dot on white or bright screens.
  • Stuck pixel: one or more subpixels stay on, so it shows as a single color such as red, green or blue. Easiest to see on black.
  • Hot pixel: always on, so it shows as a bright dot on black.

Dust is easy to mistake for a bad pixel. If the dot is still in the same place after wiping the screen with a soft cloth, it is probably a pixel defect.

How to run the test

  1. Dim the room a little and leave the screen brightness at its usual level.
  2. Press Start and scan each color slowly, section by section. Click or press → to move to the next color.
  3. On black, a hazy glow along the edges is backlight bleed. OLED screens have no backlight, so they cannot bleed.
  4. On gray and the gradients, look for blotches or stair-step bands (banding).

The 1-pixel checker and grid are drawn in physical pixels using your display scale. If they still look uneven, set your system scaling or browser zoom to 100%.

Warranty and a word of caution

How many bad pixels count as acceptable differs by manufacturer and product. For a new screen, check the seller's and manufacturer's pixel policy. Rapidly flashing patterns are sometimes suggested for unsticking pixels, but they can be dangerous for people sensitive to flashing light, so this site does not offer them.

FAQ

Does it work on phones?
Yes. Press Start to fill the screen with color and tap to move to the next one. Browsers that cannot make a page full screen, such as Safari on iPhone, fill everything except the address bar.
The refresh rate reads lower than my screen.
It is measured from how often the browser draws frames. Power saving, battery mode or heavy tabs can lower it, and variable refresh screens change rate with the situation. Try Measure again.
Can bad pixels be fixed?
Dead pixels usually cannot be fixed. Stuck pixels sometimes recover over time, but there is no guarantee. If the screen is under warranty, asking for a replacement or repair is the surest route.