Find dead and stuck pixels with a fullscreen colour test
A dead pixel test floods your screen with solid, full-brightness colours so that a single misbehaving pixel becomes obvious against the flat field. It is the standard check to run on a new monitor, laptop, phone or TV — ideally before a return window closes — and to diagnose a suspicious dot you have noticed during normal use.
Press Start fullscreen test, then click or use the arrow keys to move through white, black, red, green, blue, cyan, magenta, yellow and grey. Press Esc at any time to exit.
What each colour reveals
- White — the best background for spotting a dead pixel, which stays black.
- Black — the best background for a stuck pixel, which glows a bright colour.
- Red, green and blue — reveal faults in a single sub-pixel, which only misbehaves on its own channel.
Scan slowly from around 30 cm away. A healthy panel shows a perfectly uniform field of colour edge to edge, with no coloured or black specks.
Dead versus stuck — and what you can do
A dead pixel gets no power and is black on every colour; it usually cannot be revived. A stuck pixel is frozen on one colour and sometimes recovers if its sub-pixels are rapidly exercised or with very gentle pressure while the screen is on. If you find several faults on a new display, check the manufacturer’s dead-pixel policy — many will replace a panel above a set count.
The whole test runs locally in your browser with plain CSS colours. There is no camera access, no upload and no tracking.