Dead pixel test
Runs in this pageFill the whole screen with solid colours and look for dots that do not match. A dark dot on white is a dead pixel; a bright red, green or blue dot on black is a stuck pixel. Run it when a new monitor or laptop arrives, while you can still return it.
Black · 1/9 · Click for the next colour
Look for dots that stay one colour on every screen: black on white is a dead pixel, a bright dot on black is a stuck or hot pixel. Clean the screen first: dust looks the same but moves when you wipe.
How to use it
- Clean the screen, then press Start full-screen test.
- Look across the whole screen on each colour. Click, or press → or Space, for the next colour; H hides the label.
- Note where any odd dot is, and press Esc to leave full screen.
Details
- Colours
- Black, white, red, green, blue, grey, cyan, magenta, yellow
- Controls
- Click or →/Space next, ← back, H hide the label, Esc exit
- Works on
- Monitors, laptops, TVs with a browser, tablets and phones (full screen where the browser allows it)
Questions
Dead, stuck or hot pixel: what is the difference?
A dead pixel stays dark on every colour, best seen on white. A stuck pixel stays one colour (red, green or blue), best seen on black. A hot pixel is a stuck pixel that stays white.
Can a stuck pixel be fixed?
Sometimes. Stuck pixels occasionally recover after hours of use or gentle pressure with a soft cloth while the screen is off. Dead pixels are usually permanent. Check the maker's pixel policy: many replace a screen only above a certain number of faulty pixels.
Is it dust or a pixel?
Dust and smudges move or disappear when you wipe the screen and look grey on every colour. A faulty pixel stays in exactly the same place.
Does full screen work on iPhone?
iPhone Safari does not allow full screen for pages, so the test fills the area under the address bar. Rotate to landscape and scroll so the coloured box fills the screen.