Dead Pixel Test
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Check your screen for dead, stuck and bright pixels
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Look closely at each colour, especially black and white. A pixel that stays black on every colour is dead; one that stays lit in a single colour is stuck. Wiping the screen first rules out dust.
Why Choose Our Dead Pixel Test?
Plenty of pixel-testing pages just throw a black screen at you and call it done. This tool is built to give a more complete picture in a single pass.
12-Color Pure Test
Instead of just black and white, the tool cycles through 12 pure colors, including red, green, blue, cyan, magenta, yellow, orange, and three grey steps. Every pixel is made of red, green, and blue sub-pixels, so a fault in just one of them can hide on black or white but shows up clearly against a single solid color.
Fullscreen Immersive
Selecting any color switches the whole browser window into fullscreen mode, so there’s no toolbar, cursor, or browser chrome breaking up the display. A dead or stuck pixel near the edge of the screen is easy to miss if part of it is covered by the interface, which is why the fullscreen mode matters more than it might seem.
Zero Privacy Risk
The entire test runs locally using CSS and JavaScript. Nothing is uploaded, no camera is used, and no account or download is required, so you can check a screen you don’t even own, like one in a store, without leaving anything behind.
What Are Dead Pixels?
Screen problems fall into a few different categories, and knowing which one you’re looking at changes what you should expect from a repair or return.
Bright Pixel (Stuck Pixel)
A bright pixel stays fully lit no matter what’s on screen, usually showing as a small white or brightly colored dot against a dark background. It’s technically a type of stuck pixel where all three sub-pixels, red, green, and blue, are firing at once. Bright pixels are the most noticeable defect and the ones manufacturers are least willing to tolerate.
Dead Pixel
A dead pixel has lost power completely and stays black regardless of what color is on screen. It’s easiest to spot against white or light backgrounds. Because the transistor driving the pixel has failed rather than simply misfired, a true dead pixel is a hardware issue that no amount of testing or rapid color cycling will fix. It will remain dark even when the rest of the display changes normally.
Stuck Pixel
A stuck pixel is locked onto a single color, most often red, green, or blue, while the pixels around it continue changing normally. Unlike a dead pixel, a stuck sub-pixel is still receiving power, which is why stuck pixels sometimes recover after running through a fast color cycle for long enough. The affected pixel may continue showing the same color until it recovers or the display is repaired.
How to Test for Dead Pixels?
Testing takes about three minutes if you follow the process in order instead of jumping straight into the color cycle.
Prepare Environment
Turn your screen brightness all the way up and dim the room if you can. Turn off any blue-light filter, night mode, or dynamic contrast setting first, since these adjust color output and can either hide a genuine defect or create a false positive. Also make sure the screen is clean and free from fingerprints, dust, or smudges that could look like display defects. Keep the screen at a normal viewing angle while checking the colors.
Fullscreen Color Cycle
Pick a color from the picker, or set a custom color using the hex input, then click to start the test (or press F) to enter fullscreen mode. Use the arrow keys, the on-screen buttons, or a swipe on a touchscreen to move through all 12 colors, and turn on auto-cycle if you’d rather step back and watch from a distance. On a desktop, you can also click through the color squares with the left mouse button before starting the full-screen cycle.
Focus on Key Areas
Lean in and inspect the edges and corners of the screen first, since that’s where manufacturing defects and pressure damage tend to show up. Give each solid color a few seconds before moving on, and check the whole screen rather than just the center, since a stuck or dead pixel can hide anywhere the panel was assembled unevenly. Look for any unusual dots, lines, patches, or areas that remain noticeably different as you switch between colors.
What Causes Dead Pixels?
Dead and stuck pixels usually trace back to one of four causes.
Manufacturing Defects
A microscopic flaw in a transistor or in the liquid crystal layer during panel production can leave a sub-pixel defective before the screen ever leaves the factory. This is the most common reason a brand-new laptop or monitor already has a dead pixel out of the box.
Physical Pressure
Pressing too hard while cleaning a screen, rough handling during shipping, or a knock against a corner can damage the layer beneath the glass. This is one of the more preventable causes, since it usually comes down to how carefully a display was handled before it reached you.
Electrostatic Damage
A static discharge in a dry room can fry the tiny transistor responsible for a single pixel. It’s one reason display manufacturers recommend grounding yourself before handling an open panel.
Natural Aging
Over years of use, the circuitry or emissive material behind a pixel can wear out, especially in areas that display bright content constantly. This shows up more often on OLED panels, where individual sub-pixels age at different rates depending on what’s shown most often.
Industry Dead Pixel Standards
Screen manufacturers don’t promise a flawless panel. Most define a tolerance for how many pixel defects are acceptable before they’ll repair or replace a unit, and the numbers vary quite a bit by brand.
ISO 13406-2 Class II
ISO 13406-2 Class II is the tolerance level most consumer laptop and monitor panels are built to. It allows up to two bright pixel faults, two dark pixel faults, and five stuck sub-pixel faults per million pixels, which on a typical laptop screen can still add up to a handful of permitted defects. Acer’s own pixel policy page shows how a mainstream manufacturer applies this class in practice.
Apple Policy
Apple doesn’t publish an official pixel-defect number, but leaked internal service guidelines reported by AppleInsider have shown a tiered system that scales with screen size. Smaller displays have historically needed only a single anomaly to qualify for a repair, while larger displays allowed several bright or dark pixels before a replacement was authorized.
Dell Premium Panel
Dell’s Premium Panel Exchange offers a free panel replacement for eligible UltraSharp, Professional, and Alienware OptX monitors if even a single bright pixel is found. Dark or dead pixels aren’t covered by that specific guarantee and typically need to reach a higher count, commonly six or more depending on the model, before Dell will authorize an exchange.
General Consumer
Most budget and mid-range laptops and monitors are built to an ISO Class II style policy rather than a stricter guarantee like Dell’s. A small number of dead, stuck, or bright sub-pixel defects can legally fall within spec even on a brand-new screen, which is exactly why running a dead pixel test before your return window closes is worth the three minutes it takes.
Dead Pixel Detection FAQ
Here are some commonly asked questions about FAQs
Testing Tips
Test a new screen before you set up anything else on it. A dead pixel is far easier to notice on a plain solid color than buried behind icons and open windows, and catching it in the first few minutes keeps you safely inside most return windows.
A few other things worth doing while you test:
- Dim the room and turn brightness to maximum for the most accurate read.
- Check the edges and corners first, not just the center of the screen.
- If a colored dot looks like it might be stuck rather than dead, re-test after 24 hours before assuming it’s permanent.