Dead Pixel Test

How Do I Test a Screen for Dead Pixels?

Clean the screen with a dry microfiber cloth so that dust is not mistaken for a pixel defect.
If you are testing an external monitor, move this browser window onto that display before starting.
Set a comfortable, normal brightness and temporarily disable Night Light, True Tone, or other color filters.
Click Start test. The browser will show a solid color in full-screen mode.
Inspect the entire display from your normal viewing distance. Click or tap the screen, or press any key, to switch colors.
Check all five colors: white, black, red, green, and blue. Press Esc or Backspace to finish.

The test usually takes 1–2 minutes. Repeat the color cycle once if you notice a suspicious point.

What Each Test Color Reveals

White makes black dead pixels and dark dust specks easy to see.
Black reveals pixels that remain bright, as well as some backlight irregularities on LCD panels.
Red, green, and blue test the individual RGB subpixels. A dark or wrong-colored point on one of these screens can indicate a failed or stuck subpixel.

A solid background removes image detail that could hide a defect, making a single abnormal pixel easier to spot.

Dead, Stuck, and Hot Pixels

Dead pixel: usually remains black because it no longer emits or passes light.
Stuck pixel or subpixel: remains red, green, blue, or another fixed color as the test background changes.
Hot pixel: remains bright, most noticeably on a black background.

Manufacturers do not always use these terms in the same way. Their warranty policies may also allow different numbers and positions of defective pixels.

How to Confirm a Pixel Defect

Clean the panel and check the point again from two viewing angles.
Cycle through every test color. A physical defect stays in exactly the same place.
Take a screenshot and open it on another screen. Display hardware defects do not appear in screenshots.
For an external monitor or TV, try its built-in self-test or another input to rule out a cable, source, or graphics problem.

What to Do If You Find a Defective Pixel

Record the location and color of the defect, then check the manufacturer’s pixel policy and warranty terms. If the device is new or still within its return period, contact the seller before trying any corrective procedure.

Do not press, rub, tap, or heat the screen. These methods can damage the panel, its coating, or nearby pixels. Pixel-cycling software may sometimes change a stuck subpixel, but it cannot repair a physically dead pixel; use only procedures approved by the manufacturer.

Supported Screens and Privacy

This browser test works with desktop monitors, laptop displays, phones, tablets, and TVs connected as a display. It can be used with LCD, LED, OLED, QLED, Mini-LED, and other flat-panel technologies.

The test runs locally in your browser. It does not access your camera, files, or screen contents and does not install software.

Frequently asked questions

How do I run the dead pixel test?

Click “Start test.” Inspect the white screen, then click or tap it, or press any key, to cycle through black, red, green, and blue. Press Esc or Backspace to exit full-screen mode.

What is the difference between a dead and a stuck pixel?

A dead pixel usually stays black on every test color. A stuck pixel or subpixel stays red, green, blue, or bright even when the background changes.

Can this test repair a dead or stuck pixel?

No. This tool safely reveals pixel defects but does not repair them. Do not press, rub, or heat the panel: that can cause more damage. Follow the display manufacturer’s diagnostics and warranty guidance.

How can I tell whether the defect is in the screen or the image?

Take a screenshot and view it on another display. A physical pixel defect will not appear in the screenshot. If the mark is visible there too, the likely cause is the image, software, or graphics hardware.