Online Monitor Dead Pixel Test

How to Test Your Monitor or Laptop Screen for Dead Pixels

When buying a new monitor, TV, or laptop, checking the panel for dead pixels and backlight defects is an essential step. Even premium models from leading brands can have manufacturing flaws or shipping damage. Our online tool allows fast and accurate display diagnostics directly in your browser without installing third-party apps.

Types of Screen Defects & How to Spot Them

• Dead Pixels: Inactive subpixels that block light and appear as permanent black dots on white and colored backgrounds.
• Stuck Pixels: Subpixels frozen in one of the primary colors (Red, Green, or Blue). Most noticeable on contrasting backgrounds (e.g., a red pixel on a black or blue screen).
• Backlight Bleeding / IPS Glow: Uneven LED backlight leakage along screen edges. Best checked on a solid black background in a darkened room.
• Pressure Spots & Dust Under Glass: Bright or dark spots with soft edges caused by physical pressure or assembly dust. Best spotted on a pure white screen.

Step-by-Step Screen Diagnostic Guide

• Clean the Screen: Before starting, wipe the display with a microfiber cloth to clear dust and fingerprints so they are not mistaken for dead pixels.
• Launch Fullscreen Mode: Click "Start Fullscreen Test" at the top of the page.
• Inspect All Color Fills:
  • Black Fill: Look for glowing (stuck) pixels and evaluate backlight uniformity at screen corners.
  • White Fill: Look for black (dead) dots, dust under glass, or grey pressure shadows.
  • Red, Green, Blue (RGB): Check individual subpixel operation.

ISO 9241-307 Standards for Acceptable Defective Pixels

Most modern monitors fall under Class 2 quality. Under international ISO standards, up to 2 bright pixels, 2 dark pixels, and 5 defective subpixels per 1 million pixels are acceptable. If your display exceeds these limits, you are entitled to a warranty replacement.