How to test a monitor for dead pixels

Short answer: put solid fullscreen colours on the panel and look for dots that refuse to change. A free tool like Dead Pixel Test walks through white, black, all colours and a gradient, and its flashing mode often revives a stuck pixel.

First, wipe the screen

Dust, lint and dried droplets look exactly like bad pixels. Turn on a white screen and wipe the panel with a soft dry cloth before judging anything. When a suspicious dot survives the cloth, it is worth a closer look.

What kind of pixel is it?

• Dead pixel — never lights up: stays black on white, red, green and blue.
• Stuck pixel — never turns off: glows through the black screen, shows the wrong colour on the others.
• Hot pixel — always fully white, most obvious on the black screen.
• Dust — moves or disappears when wiped; not a pixel at all.

Run the colour walk

Open Dead Pixel Test, press Start fullscreen and step through the screens with Space or a click:

1. White first — every dead pixel shows as a tiny dark dot.
2. Black — stuck and hot pixels shine like stars.
3. Red, green, blue, cyan, magenta, yellow — a pixel stuck on one subpixel shows as a wrong-coloured dot.
4. Gradient — also reveals backlight bleed, clouding and banding, which flat colours hide.

Go slowly. One pixel of a 4K panel is 1/8,000,000 of the picture — the average test takes a couple of minutes per screen.

Try to fix a stuck pixel

If a stuck pixel appears, run the built-in flashing fix mode for 10–30 minutes. Rapid colour changes shake the liquid crystal out of its wrong state; many stuck pixels recover. A dead pixel (always black) is hardware failure — no tool will bring it back.

If the screen is new

Almost every manufacturer has a pixel-defect policy, and the problem is much easier to solve inside the return window. Record the result: a photo of the offending dot plus the test screen makes a warranty claim unambiguous. Some vendors promise zero bright pixels, others tolerate a few — check the policy of your model before arguing.

FAQ

How many screens should I check?

All ten: white, black, gray, nine colours and the gradient. Each one exposes a different defect type.

Can I test a laptop screen?

Yes — the app is tiny, works offline and is handy right after unboxing: install or run the portable exe, fullscreen, walk through the colours.

Does a stuck pixel fix really work?

Often it does, especially on IPS and OLED panels. Run the flashing mode for at least 10–30 minutes and check; if nothing changed, it may be a dead pixel, which is permanent.