Dead pixel test
Fill your screen with solid colors and fine patterns to find bad pixels.
Click or press Space or the right arrow for the next screen, left arrow to go back, Esc to leave.
Related tools
Test screen colors
Fill your screen with red, black, white, green, or blue, or run a ghosting test.
Test touch screen
Drag across a grid to find dead zones on a touch screen and check how many fingers register at once.
Test keyboard
Press any key and see it register on a full on-screen keyboard, with key codes and rollover.
What the dead pixel test includes
Eight solid colors
White, black, red, green, blue, cyan, magenta and yellow to expose every kind of stuck pixel.
Full-screen patterns
Horizontal lines, vertical lines and a checkerboard, drawn at the real pixel resolution.
Keyboard control
Space or arrow keys to step through, Escape to leave.
Private, nothing uploaded
The test runs in your browser tab. No file, key press, click or sound leaves your device.
Check for dead pixels in three steps
- 1
Clean the screen and dim the room
Dust and smudges look like bad pixels. Wipe the screen with a dry microfibre cloth first.
- 2
Start the full-screen test
Click Start. The screen fills with one color at a time. Click, press Space or use the arrow keys for the next screen.
- 3
Look for dots that do not change
On white, a dead pixel shows as a dark dot. On black, a stuck or hot pixel shows as a bright dot. Check red, green and blue too.
When to run a dead pixel test
Do it early, because return windows and warranties run out while a faulty pixel is easy to miss.
Buying a new monitor or laptop
Test it inside the return window, before a faulty pixel becomes your problem.
Checking a used phone or tablet
Look at a second-hand screen on every color before you pay.
After a screen repair
Make sure a replacement panel has no bad pixels.
Documenting a warranty claim
Know exactly which colors show the fault before you contact the maker.
Frequently asked questions
What is the difference between a dead pixel and a stuck pixel?
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A dead pixel never lights up and stays black on every color. A stuck pixel is stuck on one color, often red, green, blue or white, and shows against the other backgrounds. A hot pixel is a stuck pixel that stays bright white.
How do I tell a dead pixel from dust?
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Dust and fibres sit on the surface and can sometimes be wiped off or seen at an angle. A pixel fault is part of the panel, always in the same spot and the same color, and does not move when you clean the screen.
Why does the test include line and checkerboard patterns?
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One-pixel lines and a one-pixel checkerboard make uneven or flickering pixels easier to see and show scaling problems. The patterns are drawn at the screen's real pixel resolution, so at 100% browser zoom and 100% display scaling each line is a single device pixel. At other zoom or scaling levels the browser resamples them.
Will a dead pixel go away?
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A stuck pixel sometimes recovers with time or gentle pressure, but a truly dead pixel almost never does. If the screen is new, check the seller's or maker's policy on how many bad pixels they accept before they replace it.
Why did my browser say fullscreen was blocked?
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Some browsers, notably Safari on iPhone, do not allow fullscreen for web pages. The test then fills the whole browser window instead, which still works for finding bad pixels.
Does the test damage my screen?
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No. Showing solid colors and static patterns is normal use for an LCD or OLED panel. Do not leave a single bright pattern on an OLED screen for hours, which is true of any static image.
Check your screen now
Free, no account needed.