Let's hunt dead pixels.
Fill your screen with solid colors and look closely — a dot that stays the wrong color is a dead or stuck pixel.
Tap a color (or Start) to fill the screen. Then click/tap to cycle colors, and press Esc to come back.
⚠ The fixer flashes colours rapidly. Skip it if you're sensitive to flashing light.
How the dead pixel test works
The test fills your entire screen with one solid colour at a time using the browser's Fullscreen API — red, green, blue, white, black, cyan, magenta, yellow and gray. Each colour drives every pixel to a known state, so a defect stands out as a dot that refuses to match its neighbours. Click or tap to cycle colours, use the arrow keys to step back and forth, and press Esc to come home.
Sweep your eyes across the whole screen on each colour, ideally in a dim room. White is the best net for dead pixels (they stay black); black is best for stuck ones (they keep glowing). If you find a stuck pixel, the fixer mode rapidly cycles colours over the screen to try to jolt the frozen sub-pixel back to life. It's all just colours on a page — nothing is captured, stored or sent anywhere.
Dead pixel test FAQ
Dead pixel vs stuck pixel — what's the difference?
A dead pixel gets no power and stays black on every colour. A stuck pixel has one or more sub-pixels frozen on, so it glows a constant red, green or blue. It matters because stuck pixels can sometimes be revived, while dead ones can't be fixed by software.
Does the stuck-pixel fixer actually work?
Sometimes. Rapidly cycling colours forces the sub-pixels to switch on and off, which can free a stuck one. Leave the fixer running over the bad spot for at least 10 minutes. There's no guarantee — and it cannot revive a truly dead pixel.
How do I tell a dead pixel from a speck of dust?
Wipe the screen gently with a microfibre cloth first — dust sits on top, looks soft-edged and is most visible on light colours. A pixel defect is a sharp, perfectly aligned dot that stays in exactly the same spot on every colour.
How do I get out of the fullscreen test?
Press Esc at any time. During the normal test, a click or tap cycles to the next colour and the arrow keys step back and forth; while the fixer is running, a click or tap stops it too.
Is the flashing in the fixer safe?
The fixer flashes colours rapidly (about 8 times a second), so skip it if you're sensitive to flashing light. If your system has reduced motion enabled, the fixer automatically slows to a gentler two changes per second.