What is a Dead Pixel Test?
A dead pixel test fills your monitor, laptop, or TV screen with solid colors — red, green, blue, white, and black — so you can scan the whole display for dead pixels (stuck permanently on or off), image retention, and backlight bleed. Bright or dark spots stand out clearly against solid white or black, and single-color screens make it easy to catch a subpixel failure that only shows up in one color. You can run a full check in just a few minutes when unboxing a new monitor or before buying a used one.
How to Use
Click any color button to jump straight into fullscreen mode. Click the screen or press → for the next color, ← for the previous one, and Spacebar to start or stop autoplay. To cycle through every screen hands-free, click "Start Autoplay" — type your preferred interval (in seconds, 3 by default) into the number box built into the button, and autoplay starts immediately at that pace. Press ESC or the exit button in the top-right corner when you're done.
When This Comes in Handy
- Checking a brand-new monitor for dead pixels while it's still within the return window
- Quickly inspecting a used monitor on the spot before buying it
- Confirming whether a blemish or afterimage you noticed is an actual panel defect
- Checking the display quality of other screens, like laptops or TVs
Why do dead pixels look different depending on the color?
Every pixel on an LCD screen is made up of three subpixels — red, green, and blue — so a single failed subpixel often means that pixel can't reproduce just one specific color. For example, if only the red subpixel fails, that pixel shows up as a faint cyan tint on a white screen, stays invisible on solid green or blue screens, and appears as a dark dot only on a solid red screen. That's why checking just one color isn't enough — cycling through all three primary colors plus white and black is the only way to catch every dead pixel.
Good to know before you check
- Dead pixels (always off) and stuck pixels (always on) have different causes — stuck pixels are occasionally fixed by a flicker pattern, but true dead pixels are almost always a physical defect that software can't repair
- Dimming the screen makes bright spots (stuck pixels) easier to spot, while a brighter screen makes dark spots (dead pixels) stand out more
- Monitor makers and retailers each have their own "acceptable" threshold for dead pixel count, so it's worth checking the store's policy before you decide to return or exchange
- Patchy, uneven brightness isn't necessarily a dead pixel — it could be backlight bleed (uniformity issues), which shows up especially clearly on the grayscale pattern
Frequently Asked Questions
- Does the flicker pattern actually fix dead pixels?
- There are reports of rapid color cycling helping a stuck pixel return to normal, but this isn't a verified or guaranteed method. A true dead pixel that's permanently stuck off won't be fixed this way.
- Can I use this if my browser won't allow fullscreen?
- Yes. Even if the browser blocks the Fullscreen API, the test screen itself is built to fill 100% of the viewport with no scrolling or margins, so the check still works fine.
- Does this tool send or record anything about my screen?
- No. Every color change and screen display happens entirely in your browser — nothing is ever sent to or stored on a server.
- Can I use this on mobile?
- Yes, the same full-screen solid-color test works identically on smartphones and tablets.