What is a dead pixel and how can I identify it?

A dead pixel is a pixel that remains permanently black and does not light up regardless of what color is displayed. To identify dead pixels, display solid bright colors (white, red, green, blue) on your screen and look for tiny black dots. Dead pixels are most visible on bright backgrounds and cannot be fixed - they indicate a hardware failure.

What is the difference between dead pixels and stuck pixels?

Dead pixels remain black and never light up, while stuck pixels are stuck displaying one color (red, green, or blue). Dead pixels are caused by complete transistor failure and cannot be fixed. Stuck pixels may sometimes be fixed using pixel fixing software, gentle pressure, or by cycling colors rapidly. Stuck pixels are more noticeable on black backgrounds.

How many dead pixels are acceptable on a new monitor?

Most manufacturers allow 3-5 dead pixels on a new monitor before considering it defective, though policies vary by brand and monitor class. Premium monitors often have stricter policies. Bright (stuck) pixels usually have lower tolerance (1-2). Pixel clusters (2+ adjacent defective pixels) are typically covered under warranty. Always check your specific manufacturer's pixel policy.

Can stuck pixels be fixed?

Stuck pixels can sometimes be fixed, unlike dead pixels. Methods include: 1) Pixel fixing software that rapidly cycles colors, 2) Gentle pressure on the stuck pixel with a soft cloth, 3) Leaving the screen off for 24+ hours. Success rate varies - some stuck pixels fix themselves, others are permanent. Dead pixels (always black) cannot be fixed and require screen replacement.

What is backlight bleeding and is it normal?

Backlight bleeding is light leaking from the edges or corners of an LCD screen, most visible on black backgrounds in dark rooms. Some minor bleeding is normal in LCD monitors due to manufacturing tolerances. Excessive bleeding that's visible in normal lighting or affects large areas indicates a defect. IPS panels tend to have more bleeding than VA panels. OLED screens don't have this issue.

How do I test my screen in fullscreen mode?

Click the fullscreen button in the tool, or press F11 on your keyboard. Fullscreen mode removes browser UI and taskbars, allowing you to test the entire screen area. This is essential for detecting edge defects and backlight bleeding. Press ESC or F11 again to exit fullscreen mode.

Should I test my screen in a dark room?

Test in both normal lighting and darkness. Normal lighting reveals dead pixels and color issues better. Dark room testing is best for detecting backlight bleeding, brightness uniformity, and contrast issues. For comprehensive testing, check your screen in the lighting conditions you'll typically use it in.

Can I use this tool on my phone or tablet?

Yes! The screen test works on all devices including smartphones and tablets. It's particularly useful for testing phone screens for dead pixels before purchase or after repair. Use fullscreen mode and test in both portrait and landscape orientations for complete coverage.

What should I do if I find dead pixels on a new monitor?

Document the defects with photos showing the pixel location and count. Check your monitor's warranty and pixel policy - you may be eligible for replacement. Contact the retailer or manufacturer within the return/warranty period. Act quickly as most return windows are 14-30 days. Pixel clusters or bright stuck pixels have better chances of warranty coverage.

Why do some colors show defects better than others?

Different colors reveal different types of defects: Black backgrounds show stuck pixels (colored dots) and backlight bleeding. White backgrounds show dead pixels (black dots) and brightness uniformity. Red, Green, Blue show color-specific stuck pixels and color accuracy. Gray shows brightness uniformity and tinting. Test all colors for comprehensive screening.

Is it normal to see some color variation across my screen?

Minor color variation is common in LCD monitors, especially at edges. However, significant tinting, color shifts, or "dirty screen effect" (clouding) indicates poor panel quality. IPS panels generally have better color uniformity than TN panels. If variation is noticeable in normal use, consider calibration or warranty claim for severe cases.

How often should I test my screen?

Test immediately when you get a new monitor or device. Re-test after any physical impact, repair, or if you notice display issues. For professional use (photo/video editing), periodic testing ensures color accuracy. Most users only need to test when purchasing or troubleshooting problems.

Screen Test - Test Monitor Display Online

Test your screen and monitor display online. Check for dead pixels, color accuracy, brightness uniformity, and screen defects. Works on all devices - PC, laptop, phone, tablet.

Instructions

• Clean your screen first

• Use fullscreen mode

• Test all colors

• Check corners and edges carefully

Test Mode

Look for black dots (dead pixels)

Testing Tips

Look for black dots (dead pixels)

Look for colored dots (stuck pixels)

Check brightness uniformity

Check for smooth transitions

Screen Test - Test Monitor Display Online Tool Introduction

A comprehensive screen test tool that helps you check your monitor or display for dead pixels, stuck pixels, color accuracy, brightness uniformity, and other screen defects. Perfect for testing new monitors, diagnosing display issues, or verifying screen quality.

Whether you're buying a new monitor, troubleshooting display problems, or performing quality control, this tool provides multiple test patterns to thoroughly examine your screen.

Key Features:

Dead pixel detection test
Stuck pixel identification
Color accuracy testing (RGB, primary colors)
Brightness uniformity check
Gradient smoothness test
Contrast ratio testing
Screen burn-in detection
Viewing angle test
Fullscreen mode support
Works on all devices and screen sizes
No installation required

Perfect For:

Testing new monitors before purchase
Checking for dead or stuck pixels
Verifying color accuracy for design work
Diagnosing screen problems
Quality control for refurbished displays
Testing phone and tablet screens

Screen Test - Test Monitor Display Online User Guide

How to Test Your Screen

Preparation

Clean Your Screen: Wipe dust and smudges for accurate testing
Adjust Lighting: Test in normal room lighting conditions
Use Fullscreen: Click fullscreen button for best results
Disable Overlays: Close notifications and other windows

Dead Pixel Test

Select solid color test (Black, White, Red, Green, Blue)
Look carefully at entire screen
Dead pixels appear as black dots on colored backgrounds
Stuck pixels appear as colored dots on black background
Move close to screen for better visibility
Test all colors to identify all defective pixels

Color Accuracy Test

View primary colors (Red, Green, Blue)
Check for color uniformity across screen
Look for color shifts or tinting
Compare with reference if available
Test secondary colors (Cyan, Magenta, Yellow)

Brightness Uniformity Test

Display solid gray or white screen
Look for bright or dark spots
Check corners and edges carefully
View from different angles
Note any backlight bleeding

Gradient Test

Display gradient pattern
Check for smooth color transitions
Look for banding or posterization
Test both horizontal and vertical gradients

Understanding Test Results

Dead Pixels

What they are: Pixels that remain black regardless of displayed color

Cause: Transistor failure, cannot be fixed

Visibility: Most noticeable on bright backgrounds

Action: Check warranty, may qualify for replacement

Stuck Pixels

What they are: Pixels stuck on one color (red, green, or blue)

Cause: Sub-pixel stuck in on position

Visibility: Most noticeable on black or contrasting backgrounds

Action: May be fixable with pixel fixing tools or gentle pressure

Backlight Bleeding

What it is: Light leaking from edges or corners

Cause: Poor panel assembly or pressure on LCD

Visibility: Most noticeable on black screens in dark rooms

Action: Minor bleeding is common, severe cases may warrant return

Color Uniformity Issues

What it is: Color shifts or tinting across screen

Cause: Panel quality, backlight variation

Visibility: Noticeable on solid colors, especially gray

Action: Calibration may help, severe cases indicate defect

Manufacturer Pixel Policies

Type	Typical Policy
Dead Pixels	3-5 dead pixels may be acceptable
Stuck Pixels	Usually covered under warranty
Bright Pixels	Lower tolerance (1-2 pixels)
Pixel Clusters	2+ adjacent pixels usually covered

Tips for Accurate Testing

Test in fullscreen mode for complete coverage
View screen from normal viewing distance first
Move closer to inspect suspicious areas
Test multiple times to confirm findings
Take photos of defects for warranty claims
Test immediately after purchase while return window is open
Compare with another screen if possible

Frequently Asked Questions

Related Tools

Microphone Test - Test Your Mic Online

Test your microphone online instantly. Check if your mic is working, view real-time audio levels, and troubleshoot microphone issues. Works with all devices and browsers.

Camera Test - Test Webcam Online

Test your webcam and camera online instantly. Check if your camera is working, preview video quality, adjust settings, and troubleshoot camera issues. Works on all devices.

Mouse Test - Test Mouse Buttons, Scroll Wheel & Cursor Online

Free online mouse tester to check all mouse buttons (left, right, middle, side buttons), scroll wheel, cursor movement, and double-click speed. Instantly diagnose mouse problems on any device without installation.

Keyboard Test - Test Keyboard Keys Online

Test your keyboard keys online instantly. Check if all keys are working properly including letters, numbers, function keys, and special keys. Works on all devices.

Keyboard KeyCode Viewer - JavaScript Key Event Inspector

Interactive JavaScript keyboard event inspector. Press any key to instantly view keyCode, key, code, which, charCode, and modifier states. Essential debugging tool for web developers building keyboard shortcuts and event handlers.