Dead pixel
Stays black on every color. Its transistor never turns on, so it is usually permanent.
How to run the test
A dead pixel test takes less than a minute. The idea is simple: a faulty pixel stays the same color while the background changes, so flipping through solid colors makes it stand out.
- Clean your screen. Wipe away dust and smudges first, so you don't mistake them for dead pixels.
- Dim the lights. A darker room makes faulty pixels much easier to see.
- Go fullscreen and cycle. Hit Start test, then use the ← → keys — or tap the left and right edges of the screen — to flip through white, black, red, green, and blue. Watch for dots that never change.
Dead vs. stuck pixels
Stuck pixel
Stuck on one color — usually red, green, or blue. Sometimes fixable with gentle pressure or a rapid color-flashing video.
Dead pixel test FAQs
Can dead pixels be fixed?
Fully dead pixels (black on every background) usually can't be revived. Stuck pixels sometimes respond to gentle pressure on the area or videos that flash colors rapidly. If your device is under warranty, a cluster of faulty pixels may qualify for a replacement.
Does this work on phones, tablets, and TVs?
Yes — open this page in any modern browser and tap Start test. One caveat: iPhones can't enter true fullscreen from Safari, so cycle through the colors by tapping the screen edges instead.
Which colors reveal dead pixels best?
White exposes dead (black) pixels, black exposes stuck (lit) pixels, and red, green, and blue each reveal single-subpixel faults. That's why the test cycles through all of them, starting with the most revealing.