What is the difference between dead, stuck, and hot pixels?

Dead pixels are completely black (all sub-pixels off, transistor failed) and permanent. Stuck pixels show a fixed color (red, green, or blue) because one sub-pixel is locked on — these may be fixable. Hot pixels glow bright white permanently and are usually permanent. All three are classified under ISO 9241-307 defect standards.

Can I fix a stuck pixel?

Stuck pixels can sometimes be fixed by rapidly cycling colors for 10-30 minutes, which 'massages' the liquid crystal back to normal state. This tool includes an auto-cycle mode for this purpose. Dead pixels (black) and hot pixels (white) are usually permanent hardware failures.

How many dead pixels are acceptable?

ISO 9241-307 Class II (most consumer displays) allows up to 2 bright defects, 2 dark defects, and 5 total defects per million pixels. However, manufacturer policies vary: Dell UltraSharp replaces on 1 bright pixel, BenQ has Zero Bright Dot policy, LG requires 5+ defects. Always check your warranty terms.

Does this work on phones and tablets?

Yes. Open this page on any device with a modern browser. On iOS, the Fullscreen API is restricted, so the tool expands to maximum viewport (100vh) instead. Hide the browser address bar by scrolling or using 'Hide Toolbar' mode for best results.

Why test with 8 colors instead of just black and white?

Each pixel has 3 sub-pixels (red, green, blue). The 8 colors represent all ON/OFF combinations: white (all ON) finds dead pixels, black (all OFF) finds stuck/hot pixels, and red/green/blue reveal which specific sub-pixel has failed. Yellow/cyan/magenta provide additional contrast for edge cases.

Will this damage my screen?

No. Displaying solid colors is completely safe and does not cause burn-in or screen damage. Burn-in occurs from static images displayed for hundreds of hours, not from short-term color testing.

Can dead pixels spread to neighboring pixels?

A single dead pixel does not physically spread. However, additional unrelated pixels can fail over time on the same display. If you notice a cluster growing in one area, it usually indicates panel damage or pressure points, which may worsen.

Is my data sent to a server?

No. This tool runs entirely in your browser using the Fullscreen API. No screen data, test results, or any information is sent to our servers. Your testing is 100% private.

Tools

Custom

• Press ESC to exit

• or use Space, Arrow keys to switch colors

Dead Pixel Test — Free Online Monitor & Screen Defect Checker

Free online dead pixel tester for monitors, laptops, phones, and tablets. Display full-screen solid colors (white, black, red, green, blue, yellow, cyan, magenta) to detect dead pixels, stuck pixels, and screen defects. Test new monitors within return window, check used devices before buying, and diagnose display issues. Works on all devices with a modern browser — no download required. All testing runs locally in your browser for 100% privacy.

Features

✓Full-screen solid color display — 8 colors (white, black, red, green, blue, yellow, cyan, magenta) to expose all pixel defect types
✓Custom color support — test with any color you choose via color picker
✓Dead pixel detection — black dots that never light up, visible on white background
✓Stuck pixel detection — colored dots (red/green/blue) frozen on one color, visible on black background
✓Hot pixel detection — bright white dots that glow permanently
✓Keyboard shortcuts — Space or Arrow keys to cycle colors, Esc to exit full-screen
✓Touch support — tap screen to cycle colors on mobile devices
✓Works on all devices — monitors, laptops, phones, tablets, TVs with web browser
✓No installation required — runs entirely in browser, no software download
✓100% private — all testing happens locally, no data sent to server

How to Use

1Clean your screen with a microfiber cloth — dust and smudges can look like dead pixels
2Set screen brightness to maximum — defects are easier to spot at full brightness
3Click 'Start Test' or any color button to enter full-screen mode
4Cycle through all 8 colors using Space, Arrow keys, or tap on mobile
5Look carefully for dots that don't match the background color on each screen
6Mark any defects — dots that persist across multiple colors are real pixel defects
7Press Esc or click outside to exit full-screen mode

Frequently Asked Questions

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