How to use the dead pixel test
- Clean the screen. Dust looks like a dark pixel. Wipe the panel with a dry microfiber cloth.
- Press Start test. The dead pixel test runs full screen, so each color fills the whole display. Press Esc at any time to exit.
- Step through the colors with the arrow keys, a click or a tap. Pause on each color for 5–10 seconds.
- Scan in rows. Look from the top-left corner to the bottom-right. Lean in: defective pixels are tiny.
- Mark anything odd. Press M or the target button, then click the spot to drop a numbered marker. Markers stay put, so you can check the same spot on every color.
When you exit, the results list each marker with two quick questions that tell you what you found. A pixel that stays red, green or blue is stuck, and the stuck pixel fixer can sometimes revive it.
Dead, stuck or hot pixel? How to tell
Every pixel is made of three sub-pixels: red, green and blue. The type of defect depends on which of them fail, and how.
| What you see | What it is | Can it be fixed? |
|---|---|---|
| A dark dot on every color, easiest to see on white | Dead pixel: its sub-pixels get no power | Rarely. Check the return or warranty policy |
| A red, green or blue dot that never changes | Stuck pixel: one or two sub-pixels stay on | Often. Try a stuck pixel fixer for 10–30 minutes |
| A white dot that glows on black | Hot pixel: all three sub-pixels stay on | Sometimes. Treat it like a stuck pixel |
| A dot that moves or disappears when you wipe the screen | Dust or a smudge | Wipe the screen and test again |
A dead pixel never lights up, so it hides on black and stands out on white. Stuck and hot pixels do the opposite: they hide on white and glow on black.
How the dead pixel test works
A dead pixel test fills your screen with one solid color at a time. Each color switches every sub-pixel fully on or fully off, so a faulty one has nowhere to hide. White turns all sub-pixels on and shows dead pixels as dark dots. Black turns them all off, so stuck and hot pixels glow. Red, green and blue each test one sub-pixel color. Cyan, magenta and yellow turn one color off and two on, which reveals a single stuck sub-pixel that the primary colors can miss.
Software can’t see your panel. A browser only knows what it sends to the screen, not what the screen shows, so no website or app can find dead pixels automatically without a camera. Your eyes do the checking, and the markers keep track of what you find. Unlike a dead pixel checker or tester app, this test needs no install and works the same on a monitor, laptop, TV or phone.
If a spot is hard to see, use your phone’s camera at 2–5× zoom as a magnifier.
What to do if you find a dead pixel
- Confirm it. Check the spot on every color, then wipe the screen and run the test again. A real defect stays in exactly the same place.
- Check your return window first. A store return within the return window, often 14–30 days, is usually faster and simpler than a warranty claim.
- Read the pixel policy. Most manufacturers publish rules for how many dead or bright pixels qualify for a replacement. Many base them on the pixel-fault classes in the ISO 9241-307 standard, then set their own limits. Some replace a screen for a single bright dot; others act only above a set number. Here are the display pixel policies of Dell, LG, Samsung (in German), ASUS, Acer, Apple and Lenovo. For other brands, search for the brand name plus “pixel policy”. Keep the copied report and a close-up photo for your claim.
- Try the stuck pixel fixer for stuck and hot pixels. It flashes colors over the spot for 10–30 minutes and sometimes revives it. It can’t fix a truly dead pixel.
- Avoid pressure and heat “fixes”. Pressing on the panel or heating it can crack the screen or cause more defects.
Dead pixel test on different devices
Testing a monitor or laptop
Run the monitor dead pixel test in full screen with other windows closed. With several screens, drag the browser window to the one you want to check before you press Start. Turn off Night Light and f.lux first. They tint the colors, although dead and stuck pixels still show. If the screen glows at the edges on black, that’s backlight bleed, not dead pixels, and the backlight bleed test checks for it.
Dead pixel test on iPhone and Android
Open this page in Safari or Chrome and turn the phone to landscape. iPhone Safari can’t show web pages in true full screen, so the test fills the browser window instead. Turn the brightness up, then tap the right side of the screen to go forward and the left side to go back. Swipe down to exit.
Testing a TV or OLED screen
Open the page in the TV’s web browser, or connect a laptop over HDMI and show it on the TV. Avoid dead pixel test videos on YouTube: video compression adds blocky specks that look like defects. On an OLED screen, also look for faint shapes of logos or taskbars, which point to burn-in. The OLED burn-in test checks for it. For a broader check of colors, gradients and sharpness, use the full monitor test.