Dead Pixel Test

How to use

1. Clean the screen with a soft, lint-free cloth. Dust, smudges, a protector, coating marks, or reflections can look like a pixel anomaly.
2. Move this browser window to the monitor, laptop, phone, or tablet display you want to inspect. Close overlays and other windows that could cover the panel.
3. Click Start Test, then use Fullscreen so the solid field covers the available inspection area. Fullscreen is user-triggered; it does not start automatically.
4. Scan methodically from corner to corner on each field. The Colors shown progress counts unique fields in the current run. Use Previous/Next, Space, Left/Right, or a click/touch on the field; Autoplay advances slowly every 4 seconds and can be paused.
5. If a point looks different, check the same location on several fields before recording a local observation. Do not press, tap, or rub the panel.
6. Review all nine fields before recording a clean-round no-visible-issue observation. Use Exit or Escape to freeze the last-run coverage, then record what you observed; partial rounds remain clearly identified.

What the result means

• You are the sensor. The page draws known colors and cannot see, count, or classify panel pixels for you.
• A persistent dark point across several fields is consistent with a possible dark pixel anomaly, but dust, a surface mark, coating, reflection, or another display issue can look similar.
• A persistent bright or fixed-color point can be consistent with a possible stuck or bright subpixel. Pixel and subpixel terms are used inconsistently across products, so the page cannot identify the underlying electrical cause.
• White and bright fields make dark points easier to notice; black makes bright or fixed-color points easier to notice. Red, green, and blue isolate individual color channels, while gray and cyan/magenta/yellow add contrast combinations.
• Repeat a suspicious location across multiple colors and from a consistent viewing position. One field or one glance is not enough to identify a defect.
• No visible issue noticed means only that you did not see an anomaly during this round. It is not a pixel-perfect, panel-health, or warranty verdict.
• An observation is tied to the last ended inspection in the current page session. A partial round is not presented as a complete clean round, and no screen image, pixel coordinate, or automatic detection result is created.

Limitations

• The browser cannot inspect physical panel pixels, subpixel circuits, drive voltage, cables, graphics hardware, or an electrical root cause; this is visual inspection only.
• Dust, smudges, screen protectors, coatings, reflections, content, scaling, and other display problems can mimic a dark, bright, or colored point.
• Viewing conditions, color management, brightness, angle, browser rendering, and the display pipeline affect what you can see. Fullscreen support and behavior vary by browser and device.
• The slow 4-second autoplay is deliberate and is not a rapid-flashing or pixel-repair routine. Stop and leave the page if the display or pattern feels uncomfortable.
• Manufacturer pixel policies and return or warranty thresholds vary by product. This page does not decide whether a claim qualifies.
• The page does not photograph, record, analyze, upload, or persist the screen or the observation you choose.

Troubleshooting

Fullscreen does not enter

Use the browser's Fullscreen control from a direct user click, check that the browser allows it, and continue with the solid field if this device does not support native fullscreen.

The wrong monitor is being inspected

Exit fullscreen, move this browser window to the target display, close overlays there, and enter fullscreen again. A browser cannot choose a different physical monitor for you.

Browser chrome or mobile controls still cover part of the screen

Mobile browsers may limit native fullscreen or keep system controls visible. Rotate or use the browser's own fullscreen behavior where available; do not treat an uncovered edge as tested.

A tiny suspicious spot is hard to distinguish

Clean the surface, reduce glare, use a comfortable viewing position, and compare the same location on white, black, gray, and RGB fields. Do not press or rub the panel.

The mark may be dust or a surface defect

Clean the screen gently and check whether the mark stays fixed across several fields. A mark that changes with the surface, reflection, or viewing angle is not automatically a pixel defect.

The anomaly appears on only one color

Repeat the location on the other fields. A color-specific appearance may be a subpixel-related anomaly or another display effect; this page cannot diagnose which.

Autoplay stopped after switching tabs

The page pauses autoplay when hidden so it is not advancing unattended. Return to the tab and press Autoplay again if you want to continue the slow cycle.

Space or arrow keys do nothing

Click the test page so this tab is active, then use Space, Left, or Right. Click/touch the color field or the on-screen buttons if keyboard events are intercepted.

The screen dims or sleeps

Keep the device awake only as needed for this short inspection and follow the device's normal power controls. Wake Lock support varies and does not change the visual result.

I want to try a possible stuck-pixel intervention

Use the separate Stuck Pixel Fixer only for a suspected bright or fixed-color point. It is an optional attempt with no repair guarantee and cannot restore a genuinely dark pixel.

Related tools

• Stuck Pixel Fixer

  Position a bounded browser color-cycle patch over a suspected bright or fixed-color pixel, then recheck it on solid colors. No repair guarantee.

• Monitor Color Test

  Inspect monitor color, grayscale neutrality, near-black and near-white separation, visual gamma references, gradients, banding, and RGB clipping with locally rendered browser patterns.

• Screen Resolution

  See browser-reported screen and viewport CSS sizes, DPR, and an estimated device-pixel size. Refresh after display changes; this is not native panel telemetry.

FAQ