ScreenCheckv1.0
pixels
4 min read
Updated September 2026

How to Test for Dead Pixels on Any Monitor

Step-by-step visual inspection method to detect dead, stuck, and hot subpixels on new and existing displays.

Summary & Key TakeawayDead pixels remain black on light screens, while stuck subpixels shine red, green, or blue on black. Testing requires edge-to-edge solid color fields and careful visual scanning.

1. Prepare and Clean Your Display

Before launching any pixel test, thoroughly clean your display glass. Dust specks, dried spit marks, and fingerprints easily mimic dead pixels when viewed straight on.

Power down the monitor so the panel is cool and dark. Use a dry, clean microfiber cloth with light circular motions. Never spray liquid directly onto the monitor surface; dampen the cloth with distilled water or an electronics-safe screen cleaner if stubborn grime persists.

Action Checklist
  • Turn off the screen to spot surface dust and smudges.
  • Wipe gently with a microfiber cloth without applying excessive panel pressure.
  • Ensure room lighting is moderate so glare does not obscure panel corners.

2. Running Edge-to-Edge Solid Color Fields

Open the ScreenCheck Dead Pixel Test and enter browser fullscreen mode (F11 on Windows, Ctrl+Cmd+F on macOS, or click the fullscreen button). Browser toolbars and taskbars must be completely hidden to uncover perimeter pixels.

Cycle slowly through pure solid backgrounds: Black (0%), White (100%), Red, Green, Blue, and neutral grays (5%, 25%, 50%).

Position your eyes 30 to 45 centimeters from the screen. Scan methodically in a grid pattern: top-left across to top-right, then down row by row.

3. Identifying Defect Types

Dead Pixel: The transistor is non-responsive or has lost power. It will show up as a tiny pitch-black dot against pure white, yellow, cyan, and light gray fields.

Stuck Subpixel: One subpixel (Red, Green, or Blue) remains permanently open. It stands out brightly as a colored needle-point against a pure black or dark gray screen.

Hot Pixel: All three subpixels are stuck permanently on, glowing pure white even on a pure black background.

Technical Tip

Dust vs. Dead Pixel Test: Look at the suspected spot from an oblique 45-degree angle. If the dark spot shifts slightly relative to the luminous pixel grid underneath, it is a surface dust speck or debris trapped under the polarizer, not an electrical dead pixel.

4. ISO 9241-307 Warranty Policies

Most consumer monitors follow ISO 9241-307 Class II guidelines. Under Class II, manufacturers typically permit up to 2 permanently bright pixels, 2 permanently dark pixels, or 5 defective subpixels per million pixels before considering the panel defective.

However, "Zero Bright Dot" (ZBD) warranties specifically cover even a single stuck bright subpixel within the first 30 to 90 days. Always check your retailer or manufacturer return window immediately upon unboxing.

Browser & Hardware Limitation

Browser software cannot physically repair an unpowered dead pixel transistor. Flashing color utilities only occasionally dislodge physically stuck liquid crystal molecules on LCDs, with zero effect on electrical transistor failures.

Frequently Asked Questions

Can dead pixels spread across the monitor?

True dead pixels caused by failed thin-film transistors (TFT) do not spread like a disease. However, if the cause was physical impact or delamination, the surrounding area may gradually fail under mechanical stress.

Does running a flashing color video fix stuck pixels?

Rapid color cycling can occasionally stimulate a mechanically sluggish liquid crystal cell in an LCD panel to resume switching. However, it rarely fixes dead (unpowered) pixels or OLED subpixels.

How many dead pixels are acceptable on a new 4K monitor?

Under standard Class II policies, up to 5 dark subpixels may be tolerated on an 8.3-million-pixel 4K panel, though many premium manufacturers offer 0-bright-dot guarantees. We recommend returning monitors with defects clustered in the center of the display.