DeviceCheck Pro

Dead pixel test

Fill your screen with solid colours to spot dead, stuck and hot pixels, then check gradients for banding and dark greys for backlight bleed. Clean the screen first: dust looks a lot like a dead pixel.

Screen
IdleTestingPassFault
Tap, click or press → for the next colour · Esc to exit
Explainer

Why you need several colours to catch every fault

Each pixel is really three subpixels, red, green and blue, each switched on or off by its own tiny transistor. White is all three on; black is all three off. A faulty pixel is one where a subpixel ignores its instructions.

That’s why a single test colour isn’t enough. A pixel with a stuck-on green subpixel is invisible on a white or green screen, because green was supposed to be on there anyway. Pick a fault and a background to see when it shows.

Screen colour:

A healthy pixel always matches the screen colour.

Stuck pixel fixer

Photosensitivity warning: this flashes bright colours rapidly. Don’t use it if you or anyone nearby has photosensitive epilepsy, and don’t stare at it.

Drag the flashing square over the stuck pixel and leave it for 10 to 30 minutes. It works on some stuck pixels, never on dead ones, and it cannot damage the screen.

Dead, stuck or hot: what you’re looking at

FaultLooks likeFixable?
Dead pixelBlack dot on every colour, most obvious on whiteNo. Warranty or return
Stuck subpixelA red, green or blue dot that stays onSometimes, with the fixer or gentle pressure through a cloth (at your own risk)
Hot pixelWhite dot on blackRarely
Dust or debrisA soft grey spot; may move when you wipeYes, clean the screen

OLED screens have no backlight, so bleed and clouding don’t apply; instead look at the dark grey slide for uneven patches and at the grey slide for burn-in (faint ghosts of static images like taskbars or HUDs).

Checking a new monitor? Also measure its real refresh rate, since it’s common to find a 144 Hz screen running at 60 Hz.

Questions

How do I check for dead pixels?

Press “Start full-screen test”, then tap, click or press the arrow keys to step through solid colours. Look closely at each one: a dead pixel stays black on every colour, a stuck pixel stays one colour (red, green or blue), and a hot pixel stays white on the black screen.

Can a stuck pixel be fixed?

Sometimes. A stuck subpixel is powered but not switching properly, and rapidly cycling colours over it for 10 to 30 minutes occasionally frees it. A truly dead pixel (black on every colour) can’t be fixed by software. Always clean the screen first: dust often looks like a dead pixel.

Is the stuck pixel fixer safe?

It flashes colours rapidly, which can trigger seizures in people with photosensitive epilepsy. Don’t look at it, keep it to a small area and never run it if you or someone nearby is photosensitive. It does not harm the screen.

How many dead pixels are acceptable?

That depends on the manufacturer’s pixel policy, based on the ISO 9241-307 pixel fault classes. Many brands only replace a monitor after several faulty pixels, while some offer a zero-bright-dot guarantee. Check your warranty terms, and test within your retailer’s return window.

What else can I check on this screen test?

The gradients reveal banding (visible steps instead of smooth fades), and the uniformity greys show backlight bleed and clouding at the edges, especially on IPS and VA panels viewed in a dark room.

Other checks