How to Test for Dead Pixels (and Stuck Ones Too)
A pixel fault you find at home is worth money; one you find after the return window is worth nothing. Ten minutes with full-screen solid colors finds both kinds, tells them apart, and produces the evidence a warranty claim actually needs.
What you need
The screen, a clean microfiber cloth, and about 20–30cm of patience. Daylight or a bright room helps: hunting pixels in a dark room makes every smudge look like a defect. Works on monitors, laptops, phones and tablets; for a phone, open the test on its own browser and rotate as needed.
Step 1 — Clean first, judge second
Wipe the screen properly before you start. Dust, grease and micro-scratches masquerade as pixel defects remarkably well, and every one you "find" on a dirty panel is a false alarm. A real pixel defect never moves; dust does.
Step 2 — Run the colors, panel by panel
Open the free dead pixel test and go full screen. Click or press space to step through each solid color. Don't stare at the center. Scan slowly in rows, like reading, top-left to bottom-right, then repeat on the next color. Each color has a job: black exposes bright stuck pixels, white exposes dark dead ones, and pure red, green and blue catch single sub-pixel faults that hide on white. A suspicious dot that appears on every color is real; one that vanishes on its own color is a stuck sub-pixel.
Step 3 — Dead or stuck? It matters for the claim
A dead pixel is black on every color; the sub-pixels are finished. A stuck pixel glows one color constantly (usually red, green or blue) and is most visible on black. The distinction decides your options. Stuck pixels sometimes revive with rapid color cycling, which is free and worth an overnight try; dead ones essentially never do. Warranty policies treat them differently too, and bright stuck pixels are more often covered than single dead ones.
Step 4 — The screenshot trap
Here is the classic misdiagnosis: you take a screenshot to document the dot, and the dot is in the screenshot. That proves it is a graphics or driver artifact, not a panel defect. Real pixel faults are physical, and screenshots (which bypass the panel) never capture them. Conversely, if you can't reproduce the dot in a screenshot but see it on screen, you are looking at genuine panel hardware. For evidence, photograph the screen with a phone against a solid color.
Step 5 — Check the policy before you escalate
Manufacturers follow pixel-class policies (rooted in ISO standards like 13406-2): many treat a small number of dead pixels on a high-resolution panel as within spec, while bright stuck pixels on dark backgrounds often cross the line. Look up your brand's exact policy, note the pixel's position and color against a solid fill, and photograph it. A claim that arrives with "bright green stuck pixel, center-left, visible on black, photographed" gets approved; "there's a dot somewhere" gets a tutorial link.
Frequently asked questions
What is the difference between a dead and a stuck pixel?
A dead pixel shows black on every color because its sub-pixels no longer light up at all. A stuck pixel is jammed on one color (usually red, green or blue) and is visible on white or black but not on its own color. Stuck pixels can sometimes be revived; dead ones rarely are.
How close should I look during the test?
About 20–30cm away, and clean the screen first: dust and smudges masquerade as defects surprisingly well. Let each solid color fill the screen and scan slowly, panel by panel, rather than staring at the center. Black finds bright stuck pixels, white finds dark ones, and the pure red/green/blue screens expose single-sub-pixel faults.
How many dead pixels count as a warranty defect?
It depends on the maker and the panel class. Many manufacturers follow ISO 13406-2 style classes: a common reading is that a handful of dead pixels on a high-resolution panel is "acceptable", while bright stuck pixels on dark backgrounds are often not. Check your manufacturer policy before claiming, and screenshot or photograph the defect against a solid color as evidence.
Can software really fix a stuck pixel?
Sometimes. Rapidly cycling colors at a stuck pixel can nudges a misaligned liquid crystal back into place, and it costs nothing to try. It does nothing for a truly dead pixel. If a stuck pixel survives a few hours of cycling, it is effectively permanent.
Can a dead pixel spread to the pixels next to it?
No. Each pixel is an independent cell; one failing does not damage its neighbors. What you are often really seeing is a cluster that failed together at the factory, or a growing bright spot that is heat or pressure damage. The practical difference: a single pixel that stays put is covered by whatever the panel policy says, while a spreading bright spot is worth pushing on regardless of count.
Why does the defect only show on some colors and not others?
Because a pixel is made of three sub-pixels — red, green and blue — and each can fail independently. A stuck blue sub-pixel is invisible on a blue screen and obvious on yellow. That is exactly why the test runs a full color cycle: a defect that hides on white but shows on cyan is still a real defect, just a sub-pixel one. See it on any single color and it counts.
Is OLED burn-in the same as a stuck pixel?
No. A stuck pixel is a single cell stuck on or off. Burn-in is a whole region of the panel that has aged unevenly and shows a ghost image on gray backgrounds. The test tells them apart: a stuck pixel is a single point on every solid color, while burn-in is a shape (a logo, a taskbar) that fades in and out as the gray level changes.
I found a line of pixels, not a single one. Is that a scratch or a fault?
A vertical or horizontal line of dead pixels is a separate fault — usually a failed display cable or driver chip, not damage. A scratch, by contrast, stays visible when you look at the panel from an angle and often catches the light. If it is a line, screenshot the solid-color screen and get to the warranty desk; line faults are much more likely to be replaced than single dead pixels.