HexScreen / Pixel test
Tool · Free · In your browserFind dead and stuck pixels.
Cycle through nine test colors in fullscreen by clicking or pressing the arrow keys, and check your display systematically.
In fullscreen: click, Space or → for the next test color.
What the tool does
Dead pixels
Stay dark on every color; easiest to see on white.
Stuck pixels
Permanently lit in one color; visible on black.
New purchase
Test right after buying, while you can still return it.
Buying used
Check a display in seconds before you buy.
Good to know
Dead or stuck pixel?
A dead pixel is permanently black because it no longer receives power. A stuck pixel constantly shows red, green or blue. Stuck pixels can sometimes be freed by rapidly changing colors or gentle pressure with a soft cloth.
How to test properly
Clean the display first so dust is not mistaken for pixel defects. Then go through all colors in fullscreen and look at the screen from a normal distance.
Frequently asked questions
How do I start fullscreen mode?
Click the preview, the “Start fullscreen” button, or press the F key. Press Esc or double-click to exit.
Does it work on phones and tablets?
Yes. Android and most desktop browsers use true fullscreen. On iPhone the color fills the browser window; add the page to your home screen for true fullscreen.
Can I change the color in fullscreen?
Yes. Move the mouse or tap the screen to show the color bar, or use the arrow keys.
Is a bright screen bad for my eyes?
Not with normal use. Lower the brightness for longer sessions and take regular breaks.