Dead Pixel Test
Fill the screen with solid colors to find dead, stuck and hot pixels.
- Wipe the screen and turn the brightness up, so dust is not mistaken for a bad pixel.
- Press Start test. The page fills the screen with one solid color.
- Click, tap or press the right arrow for the next color, the left arrow to go back, and Esc to exit.
Look for dots that do not match the color: bright dots on black, dark dots on white, and colored dots on the other screens. Colors change only when you ask. Nothing flashes.
How to use
Wipe the screen and turn the brightness up first, so dust or a smudge is not mistaken for a bad pixel. Then press Start test. The page fills the whole screen with one color.
Click, tap or press the right arrow or Space for the next color, and the left arrow to go back. Black reveals pixels that stay lit, white reveals pixels that stay dark, and red, green and blue reveal a single subpixel that is stuck. Gray helps you notice uneven areas.
Look over the whole screen from your normal distance, then check the corners and edges up close. The pointer and the controls hide after a moment so they do not cover anything. Press Esc or Exit to finish.
Colors change only when you ask, and nothing flashes, so the test is safe for people who are sensitive to flashing light.
FAQ
What is the difference between a dead, stuck and hot pixel?
A dead pixel stays dark and shows as a black dot on a white screen. A stuck pixel has one or more subpixels that stay on, so it shows as a red, green or blue dot on screens of another color. A hot pixel stays fully lit and shows as a bright dot on a black screen.
Can a stuck or dead pixel be fixed?
A stuck pixel sometimes recovers on its own or after gentle pressure with a soft cloth, but there is no reliable fix, and a dead pixel usually stays dead. Tools that flash colors rapidly to unstick pixels can trigger seizures in people with photosensitive epilepsy, so this test does not include one. If the screen is new, check the manufacturer's pixel policy, which states how many defective pixels qualify for a replacement.
Why does the test not go full screen on my iPhone?
Safari on iPhone only lets videos enter full screen, not web pages. The test fills the browser window instead. Turn the phone sideways and scroll a little so the address bar shrinks, which leaves more of the screen visible.
Can I check for backlight bleed with this test?
Yes. Use the black screen in a dark room with the brightness turned up. Light leaking from the edges of an LCD panel is backlight bleed, and a faint glow that changes with your viewing angle is usually IPS glow. OLED screens have no backlight, so they do not bleed.
Does this work on laptops, TVs and phones?
Yes. Any screen with a current browser works. For a TV, open the page in the TV browser or in a browser on a computer connected by HDMI, so the colors fill the TV itself.