What This Tool Does and Who It Is For
The Dead Pixel / Stuck Pixel Test displays solid colors across your entire screen to help you identify defective pixels on monitors, laptops, tablets, and smartphones. A dead pixel appears as a persistent black dot even when displaying bright colors, while a stuck pixel shows a fixed red, green, or blue color regardless of the background. This tool is essential for anyone who has just purchased a new display, suspects screen damage, or wants to verify their monitor’s condition before a return period expires.
IT professionals, photographers, graphic designers, and gamers rely on pixel-perfect displays for their work. This test helps you detect issues that might affect color accuracy, image quality, or your viewing experience. It’s also valuable before buying or selling used displays, filing warranty claims, or troubleshooting screen problems.
How to Use the Tool Step by Step
Step 1: Choose a solid color by clicking one of six color buttons: Black, White, Red, Green, Blue, or Yellow. The selected color fills your entire screen in fullscreen mode.
Step 2: Examine your screen carefully for any pixels that don’t match the background color. Look at all areas methodically, moving your eyes in a grid pattern from top to bottom.
Step 3: Click anywhere on the fullscreen display or press the Escape key to return to the control panel.
Step 4: Test with different colors. Black and white backgrounds make colored stuck pixels most visible, while colored backgrounds help identify dead pixels and other stuck pixel types.
Step 5: Use “Flash Colors” to rapidly alternate through all six colors at 200-millisecond intervals. This rapid flashing may help unstick pixels by exercising the transistors.
Step 6: Use “Cycle Colors” to slowly rotate through all colors at 2-second intervals for a more comfortable thorough examination.
How the Tool Works
The tool uses six pure colors displayed at maximum intensity: pure black (#000000), pure white (#FFFFFF), pure red (#FF0000), pure green (#00FF00), pure blue (#0000FF), and pure yellow (#FFFF00). When you click a color button, JavaScript displays that color as a fullscreen overlay covering your entire viewport at 100% width and height.
The Flash Colors mode cycles through all six colors automatically, changing every 200 milliseconds (5 times per second). The Cycle Colors mode changes colors every 2000 milliseconds (2 seconds), providing a slower, more methodical examination.
Worked Example:
| Color Selected | Hex Value | What You Should See | Def ective Pixel Appearance |
|---|---|---|---|
| Black | #000000 | Completely black screen | Stuck pixel shows as red, green, or blue dot |
| White | #FFFFFF | Completely white screen | Dead pixel shows as black dot |
| Red | #FF0000 | Solid red screen | Dead pixel is black; green/blue stuck pixels visible |
| Green | #00FF00 | Solid green screen | Dead pixel is black; red/blue stuck pixels visible |
| Blue | #0000FF | Solid blue screen | Dead pixel is black; red/green stuck pixels visible |
The tool doesn’t perform calculations—it provides a controlled testing environment where pixel defects become immediately visible against uniform backgrounds.
How to Read the Results and What to Do Next
If every pixel on your screen displays the correct color across all six test colors, your display is functioning perfectly. If you identify problem pixels, note their exact location and appearance.
Dead pixel: Appears black on all backgrounds, including white. This indicates the pixel’s transistor is permanently off. Dead pixels typically cannot be repaired and may qualify for warranty replacement depending on manufacturer policies.
Stuck pixel: Shows a constant red, green, or blue color. The pixel’s sub-pixel is stuck in an “on” position. Run the Flash Colors mode for 10-30 minutes—the rapid color changes sometimes unstick pixels by exercising the stuck transistor. Some users report success rates of 20-60% with this method.
Document your findings with screenshots or photos showing the defective pixel against a contrasting background. Check your manufacturer’s dead pixel policy—many require a minimum number of defective pixels (often 3-8) before authorizing replacement. Contact support within your warranty or return period if the defects are unacceptable.
Why You Need This Tool and When It Is Most Useful
Display defects are easier to spot during controlled testing than during normal use. You might not notice a single stuck pixel in complex images or video, but it becomes glaring on solid backgrounds during professional work. Testing immediately after purchase lets you return or exchange defective units within the return window.
The tool is most useful when unboxing a new monitor, after screen repairs, when experiencing visual anomalies, before warranty expiration, when selling or buying used displays, and after physical impacts that might cause pixel damage. Testing in a dark room with screen brightness at 100% provides the most accurate results.
For professionals who require color accuracy—photographers, video editors, designers—even a single stuck pixel in a critical screen area can interfere with work. Early detection prevents working with a compromised display for months before noticing the issue outside the return period.
Limitations of This Tool
This test only detects dead and stuck pixels—it doesn’t measure color accuracy, brightness uniformity, response time, refresh rate issues, or backlight bleed. It cannot diagnose the cause of pixel defects or predict whether additional pixels will fail.
The tool cannot fix dead pixels, only potentially unstick stuck pixels through the flashing function. Success with stuck pixel repair is not guaranteed. Very small defects might be difficult to see on high-resolution displays. The test doesn’t account for temporary image retention or burn-in, which requires different testing methods.
Some manufacturers distinguish between “stuck” and “bright” pixels in warranty terms, and this tool doesn’t provide that technical classification. The tool also won’t detect intermittent pixel issues that only appear under specific conditions like certain temperatures or viewing angles.
Frequently Asked Questions
How many dead pixels are acceptable on a new monitor?
This depends on the manufacturer’s pixel policy, which varies widely. Some premium brands replace displays with even one dead pixel, while others require 3-8 defective pixels or specific patterns (such as a stuck pixel in the center area). Check your specific product’s warranty terms, as standards differ by screen size and resolution.
Can the flashing colors mode damage my screen?
No. The Flash Colors mode changes colors every 200 milliseconds, which is well within safe operating parameters for all modern displays. However, people sensitive to flashing lights should avoid this mode. The flashing may help unstick pixels but will not harm functioning pixels.
Why do I need to test with multiple colors instead of just white?
Different defects are visible against different backgrounds. A stuck red pixel is invisible on a red background but obvious on black, white, green, or blue. Dead pixels show clearly on white but might be missed on black. Testing with all six colors ensures you catch every type of defect.
How long should I run the Flash Colors mode to try fixing a stuck pixel?
If you’re attempting to unstick a pixel, run the Flash Colors mode for 10-30 minutes initially. Some users report success after several hours. If you see no improvement after 30 minutes, continued flashing is unlikely to help. There’s no harm in trying longer, but results typically appear within the first session if the method will work.
What’s the difference between a dead pixel and a stuck pixel?
A dead pixel is permanently black on all backgrounds because its transistor is completely non-functional. A stuck pixel displays a constant color (red, green, or blue) because one or more of its sub-pixels is stuck in the “on” position. Dead pixels cannot be repaired, while stuck pixels sometimes respond to the flashing technique.
Should I test my display at maximum brightness?
Yes, for the most thorough test. Stuck pixels are most visible at higher brightness levels, and testing in a dark room at 100% brightness gives you the best chance of spotting subtle defects. However, make sure this brightness level is comfortable for your eyes during the examination.