Simple Screen Tester helps you detect dead pixels on your device screen, right in your browser. Device screens contain only three types of pixels: red, green, and blue. Any other color is a combination of these three.

This site provides a separate full-screen page for each base color so you can check each type of pixel separately. Use the small buttons at the bottom of each test page to switch colors or return home. Look at the screen carefully to notice black or white dots on red, green, blue, white, black, or gray-filled screens.

Tip: Clean your screen with a soft cloth before testing so dust particles and fingerprints won't interfere with the test.