Dead Pixel Test

Check the full panel at normal viewing distance and lighting; this is a visual inspection aid rather than automated pixel classification.

Test color

Custom color

Use fullscreen, then ← / → to change colors

White test screenInspect at normal viewing distance and close range. A visual test can help reveal unusual pixels, but it cannot determine a manufacturer’s warranty classification or distinguish every panel defect automatically.

More display patterns Check banding Measure refresh rate

What the browser can measure

Start with a functional check, measure only what the browser can actually expose, then retest after one change.

ConnectChoose the actual browser-visible device or grant permission when required.

TestConfirm basic signal, input, output, preview or display behavior.

MeasureUse browser-exposed levels, timing, resolution, FPS, axes or event data.

DiagnoseCompare the symptom with the specific diagnostic instead of relying on one number.

RetestRepeat after changing the device, cable, permission, browser or system setting.

Pre-call Mic Webcam Keyboard Mouse Gamepad Display Permissions

Browser boundary
These tools observe browser APIs and local media/event streams. They cannot certify hardware condition, bypass denied permissions, or expose measurements the browser/OS does not provide.

Dead Pixel Test: Guided Color & Coverage Checklist

Run a guided high-contrast color sequence with dwell timing and a clear boundary between visual inspection and hardware diagnosis.

Quick-win audit

Dwell per color (s)

What this tool checks

Inspect a display with fullscreen solid-color fields and controlled color changes.

How to use the result

Check the full panel at normal viewing distance and lighting; this is a visual inspection aid rather than automated pixel classification.

Privacy & browser limits

Device streams and input events used by this page are handled in your browser unless the page explicitly says otherwise. Permission, label, timing and hardware-field availability depend on the browser and operating system.

Visual defect inspection now exposes the browser/display boundary

Solid-color tests remain manual visual inspections. The review shows CSS test-area size, DPR-based device-pixel estimate and fullscreen state without claiming automatic dead-pixel detection or warranty classification.

Practical guide and verification

Use the tool first, then apply these checks to verify the inputs, interpret the result, and hand it off without displacing the primary workflow.

Test multiple solid colors, not only black and white

A pixel or subpixel defect can appear only on certain channel combinations. Cycle red, green, blue, white, black, gray, and a few dark shades while the screen is clean. A mark that stays in the same physical location across colors deserves closer inspection than one that moves with page content.

Use fullscreen at native scaling when possible

Browser chrome, page margins, display scaling, mirroring, and zoom can complicate visual inspection. Fullscreen reduces distractions, while native panel resolution and normal viewing distance make the test more representative. The browser cannot bypass operating-system scaling or prove that every physical panel pixel is addressed one-to-one.

Separate panel defects from dust and image retention

Dust, fingerprints, stuck UI overlays, temporary image retention, GPU artifacts, and damaged pixels can look similar. Clean the display appropriately, move or hide software elements, and retest after showing changing content. A browser color test is visual evidence, not a hardware diagnostic that identifies the electrical cause.

Record evidence before seeking service

If a defect persists, note the screen location, colors that reveal it, display resolution, scaling, and whether it appears in screenshots. A physical panel defect often will not appear in a screenshot captured by the computer. Warranty pixel policies vary by manufacturer and model, so compare your evidence with the applicable policy rather than assuming one universal threshold.