How do I test my monitor for dead pixels?

Open screen.diy, press F or click the fullscreen button, then cycle through full screen white, black, red, green, and blue. Dead pixels appear as tiny dots that stay black on white or stay lit on black. Inspect the entire panel slowly from a normal viewing distance.

How do I test for stuck pixels?

Stuck pixels stay one color (often red, green, or blue) on every background. Use screen.diy full screen solid colors — especially black and white — and look for bright or wrong-colored dots. Test each primary color to see which subpixel is stuck.

How can I check backlight bleed on my monitor?

Select full screen black on screen.diy, dim the room lights, and look at the corners and edges for uneven glow or light patches. IPS panels often show mild bleed; severe clouding may indicate a panel issue worth returning during warranty.

How do I make my second monitor completely black?

On the display you want to darken, open screen.diy, choose Black from the color bar, and enter fullscreen with F or the maximize button. The UI auto-hides after 1.5 seconds for a clean blackout — ideal for movies, dark rooms, or reducing distraction.

What colors should I use for a dead pixel test?

Use white to find dark dead pixels, black to find bright stuck pixels, and pure red, green, and blue to isolate faulty subpixels. screen.diy provides all of these in one click with adjustable brightness.

Is screen.diy free? Do I need to install anything?

Yes — screen.diy is 100% free with no account required. It runs entirely in your web browser with no download. Your display settings stay local; we do not collect personal data or use tracking cookies.

How do I enter fullscreen for screen testing?

Click anywhere on the background or press the F key, or tap the fullscreen icon in the bottom control bar. Press Esc to exit fullscreen. Works on Windows, macOS, Linux, and most modern browsers.

Can I use this tool on a TV or laptop display?

Yes. Open screen.diy in a browser on your laptop, desktop, or smart TV browser, pick a solid color, and go fullscreen. It is a simple online display test for any screen that supports a modern web browser.

screen.diy — Free Dead Pixel Test, Black Screen & Full Screen Color Tool

Free online monitor test: full screen black, white, red, green, and blue for dead pixel tests, stuck pixel checks, backlight bleed, and second monitor blackout. No install required.

Dead pixel test online

Use full screen solid colors to find dead pixels (dark dots on white) and stuck pixels (bright dots on black). Cycle RGB to test subpixels on any monitor or laptop display.

Black screen for second monitor

Open screen.diy on the display you want to darken, select black, and use fullscreen for a clean blackout.

How to test your monitor

Visit screen.diy in your browser.
Pick a test color (white, black, red, green, or blue).
Enter fullscreen and inspect the panel for defects.
Repeat with other colors to catch stuck or dead subpixels.

Enable JavaScript for the interactive color picker and brightness controls.