How to check a monitor for dead pixels

A dark dot, bright speck, or tiny colored mark can make you wonder if your monitor has a dead pixel. It could also be dust, a mark on the screen, or a problem in the image being displayed.

The Display Test shows solid colors that make pixel defects easier to see. Use it to check whether the mark stays in the same place as the screen changes, then follow the steps below to work out what to do next.

Check the monitor for dead pixels

Open the Display Test on the monitor you want to inspect. If you use more than one screen, make sure the test is on the screen with the suspected problem.
Use the test's color views one at a time. Look across the whole panel, not just the center. A black spot is easiest to see against a light color, while a bright spot stands out against black.
Check the same location on several colors. Note whether the mark stays fixed while the background changes, and whether it looks black, white, or one color.
If the mark might be on the surface, turn off the display and gently clean the area with a soft microfiber cloth. Turn the monitor back on and repeat the check. Do not press hard on the panel.

Inspect from a normal viewing distance first, then move closer if needed. A phone camera can add colored speckles or patterns that are not visible to your eye, so trust what you can see directly on the monitor.

What the result means

A dot stays in the same place across different colors

A mark fixed to one spot on the panel is likely a pixel or subpixel problem. A pixel is made of tiny red, green, and blue parts called subpixels. Depending on which part has failed or become stuck, the spot may look black, white, or colored. The exact terms vary between manufacturers. For a closer explanation, see stuck pixel vs. dead pixel.

The mark changes color or disappears on some backgrounds

A subpixel may be stuck on, or the mark may come from the image rather than the panel. Check another color view and another app or webpage. If the mark is visible in a screenshot when you open that screenshot on a different screen, it is part of the image or software output, not a physical pixel on the monitor.

The mark moves when you clean the screen

It was probably dust or residue on the surface. Turn the display off before cleaning so you can see smudges more easily. Follow the monitor maker's cleaning instructions, and avoid spraying liquid directly onto the panel.

A line or large area looks wrong

A full line, flickering region, or broad patch of missing color is not the usual pattern of one dead pixel. It can point to a cable, graphics, or panel problem. Check the cable and try another device before assuming the monitor panel is faulty.

How to fix it

Check that the mark is on the panel. Open a few different images or apps and repeat the color test. A mark that stays in one physical spot on the monitor is different from a speck that follows a particular image.
Reconnect the video cable. For an external monitor, unplug and reconnect both ends of the HDMI, DisplayPort, or USB-C cable. If possible, try another cable and another port.
Check the display resolution. On Windows 11, open Settings › System › Display and check that the monitor is using its recommended resolution. On macOS, open System Settings › Displays and select the display's default or recommended setting. A wrong resolution can make an image look uneven, but it will not repair a physical pixel.
Restart the computer and monitor. Turn the monitor off, restart the computer, then turn the monitor back on. This can clear a temporary graphics or connection problem.
Test the monitor with another device. Connect a different computer or device if you can. If the same mark stays in the same place during the color test, the monitor itself is the likely source.

When it's a hardware problem

If a fixed spot remains visible across the test colors and on more than one connected device, software settings are unlikely to fix it. Check the manufacturer's warranty and pixel policy before attempting a repair. Some policies allow a certain number or type of pixel defects, and the rules vary by model.

A pixel-fixing video or flashing pattern may help some stuck pixels, but it cannot reliably repair a dead pixel. Do not press, rub, or heat the screen to try to change it. If the spot is distracting and the monitor is covered, contact the seller or manufacturer. If it is outside the warranty period, compare the cost of a panel repair with replacing the monitor.

Why the background color matters

A pixel can be hard to see when its color is close to the background. A black defect may blend into a dark image, while a subpixel stuck red can disappear against a bright red screen. Checking several solid colors makes the contrast change and helps reveal a defect that one test color would hide.

The Display Test checks how the panel looks. It cannot determine the manufacturer's warranty decision or prove whether a pixel can be repaired.