Display Quality Diagnostic
Free Screen Test Online — Dead Pixel & Display Check
Display fullscreen solid colors to inspect your monitor for dead pixels, stuck pixels, backlight bleed, and color uniformity issues.
Essential when unboxing a new monitor, checking a used display, or after a screen repair.
How many of the six test colors you have checked.
The color currently displayed on screen.
Whether the test is running in fullscreen mode.
How To Use It
- Click a color swatch below to display it fullscreen.
- Examine every area of your screen for pixels that do not match the background.
- Click or press arrow keys to cycle through all colors, then exit.
Troubleshooting
- Dead pixels appear as black dots on any color. Stuck pixels show a fixed color (usually red, green, or blue).
- Clean your screen first — dust or smudges can look like pixel defects.
- Check the screen from different angles to spot backlight bleed, which appears as light spots on dark backgrounds.
More Device Checks
Grant mic access, watch a live input meter, and record a short sample to confirm that your voice is coming through.
VIDEO INPUTWebcam TestPreview your camera, switch devices, mirror the view, and capture a frame before your next meeting or stream.
AUDIO OUTPUTSpeaker TestPlay short pings, stereo checks, and pulse patterns so you can confirm your speakers or headphones are outputting sound.
INPUT DEVICEKeyboard TestPress keys on your physical keyboard and watch them light up on a virtual layout to catch dead or inconsistent inputs.
AUDIO FREQUENCYSound TestPlay frequency tones, bass checks, and a full 20 Hz–20 kHz sweep to verify your audio output and hearing range.
POINTER DEVICEMouse TestClick, scroll, and move your mouse inside a test area to verify every button, the scroll wheel, and tracking accuracy.