Dead Pixel Test
Prepare the screen
Clean the panel, open the test in fullscreen, then scan slowly from corner to corner. A dead pixel usually stays dark on bright colors; a stuck pixel stays bright or colored on dark screens.
Use this dead pixel test to inspect a monitor, laptop panel, tablet or phone screen with full-screen color patterns. Switch between white, black, red, green, blue, gray, checkerboard, grid, gradient, color bars and a fast stuck-pixel flash so tiny panel defects stand out without installing software or uploading anything.
How to check a screen for dead pixels
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1
Prepare the panel
Clean dust and fingerprints, set a comfortable brightness and dim strong reflections so small dots are easier to see.
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2
Scan solid colors first
Use white, black, red, green and blue in fullscreen. Move your eyes slowly across the screen and check the edges as well as the center.
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3
Use detail patterns to confirm
Checkerboard, grid, gradients and color bars help separate a single bad pixel from scaling blur, banding or broader uniformity problems.
What the dead pixel test shows
A screen is made of tiny pixels, and most color panels split each pixel into red, green and blue subpixels. A dead pixel usually stays dark because it is not emitting light when it should. A stuck pixel usually stays red, green, blue or bright because one subpixel remains on. Larger cloudy patches, edge glow, tint shifts or visible bands are normally panel uniformity issues rather than one isolated pixel.
Solid colors are the fastest way to find point defects. White exposes dark dots. Black exposes bright stuck pixels and backlight bleed. Red, green and blue isolate individual subpixels. Gray is useful for tint shifts and pressure marks. Detail patterns add context when a mark is hard to classify.
Pattern guide
| Pattern | Best for | What to look for |
|---|---|---|
| White | Dead pixels, dust, dark marks | One tiny black dot that does not move when you clean the screen |
| Black | Stuck pixels, glow, bleed | Bright colored dots or uneven light near the edges |
| Red / green / blue | Subpixel defects | A dot that disappears on some colors but not others |
| Gray | Uniformity and tint | Pink, green or yellow patches across a larger area |
| Checkerboard / grid | Scaling and sharpness | Blurry lines, uneven geometry or obvious pixel response problems |
| Gradient / bars | Banding and color shifts | Steps where a smooth transition should be visible |
Worked inspection routine
Start with white in fullscreen and scan from the top-left corner to the bottom-right corner. If you see a dark point, lightly clean the area and repeat; dust and tiny fibers can look like dead pixels. Next use black. A dot that glows red, green, blue or white on black is more likely to be stuck. Then run red, green and blue. If the dot appears only on one primary color, you may be seeing a single subpixel fault.
For a new monitor, repeat the test at normal working brightness and again near maximum brightness. Some defects are only obvious at one setting. If you find a problem, photograph the screen with the pattern visible and check the warranty or return policy before trying any pressure-based fix.
Safety and limits
- Do not stare at the flash pattern for long periods, especially in a dark room.
- Avoid pressing hard on the panel. Physical pressure can create new marks or cracks.
- This browser test cannot repair hardware; it only helps you see and describe symptoms.
- Very high-DPI screens can make individual pixels difficult to photograph with a phone camera.
Frequently Asked Questions
No. The patterns are generated with HTML, CSS and browser APIs on your device. The tool does not upload screenshots, camera images or screen data.
A dead pixel usually stays dark on bright colors. A stuck pixel usually stays red, green, blue or bright when the surrounding screen changes color.
Sometimes a rapidly changing pattern can make a stuck subpixel less noticeable, but there is no guarantee. Stop if the pattern is uncomfortable and check the manufacturer warranty before trying risky fixes.
That often points to a subpixel issue. For example, a defect may be visible on red but not on green or blue because only one color channel is affected.
Yes. Fullscreen removes browser chrome, makes the pattern cover the whole panel and helps you inspect the edges where bleed, glow and stuck pixels can be missed.
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