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Dead pixel test

Go full screen and step through the colours. Look closely at each one.

  • Runs in your browser
  • Nothing uploaded
  • No sign-up
  • Tells you how to fix it

Pick a colour, then press Full screen. Tap, click or press → to change colour; Esc to exit.

Tap / click / → next colour · Esc to exit

Nothing to upload — it’s just your screen showing colours.

What you are looking for

Dead pixelBlack on every colour, including white. Cannot be fixed; many warranties replace a panel above a certain count.
Stuck pixelShows one colour (often red, green or blue) regardless of the background. Sometimes recovers; see below.
Bright/hot pixelWhite on a black screen.
Backlight bleed / cloudingLighter patches on the black screen, usually at edges. Normal in small amounts on LCDs; OLED has none.
Uneven colourOn grey, a tint on one side — panel uniformity, common on cheap panels.

Trying to revive a stuck pixel

Leave the auto-cycle running for 20–30 minutes; rapid colour changes can unstick a sub-pixel. Gently pressing the spot with a soft cloth while cycling helps some panels; never press hard on OLED or phones. If it stays, note it in your warranty claim with a photo on a white and a black screen.

Buying a used monitor or phone?

Run this test in the shop: white for dead pixels, black for bright pixels and bleed, grey for uniformity.

Related tests

White screenWhite, black and colour screensRefresh rate testReal Hz, judder checkScreen resolutionResolution, DPR, HDR, gamut, ruler

Questions, answered

How many dead pixels are “normal”?

Manufacturers follow ISO 9241-307 classes: Class I allows none; most consumer panels are Class II, which tolerates a few per million pixels. Check your maker’s policy before claiming.

Does this work on a TV?

Yes — open the page in the TV’s browser or cast it, then full screen each colour.