Dead Pixel Test
Fill your screen with 5 solid colors, one at a time, and look for any pixel that does not match.
Getting ready…
How It Works
A screen is a grid of pixels, and each pixel has a red, a green and a blue subpixel. A dead pixel never lights. A stuck pixel is lit all the time, usually in one color. On a busy picture they hide; on a solid color they stand out.
The test fills the whole screen with black, white, red, green, blue, in that order. Black shows pixels that stay lit, white shows pixels that stay dark, and each primary color isolates one subpixel.
Your browser cannot see the physical screen, so you are the sensor: look over every part of it on each color. When you finish, tell the test what you saw and it records the result.
Interpreting Your Result
A black dot that stays black on every color is a dead pixel. It gets no power, and it is almost never fixable at home. Check your warranty: most makers replace a panel above a set number of dead pixels.
A dot that stays red, green, blue or white is a stuck pixel. It is getting power but is frozen, and stuck pixels can often be revived by rapidly flashing colors over them with the stuck pixel fixer.
A dot that moves when you scroll or disappears when you wipe the screen was dust, not a pixel.
Testing a new laptop or monitor? Check every key with the keyboard tester before the return window closes, and make sure the screen runs at the speed it is sold at with the refresh rate test.
Frequently Asked Questions
What is the difference between a dead pixel and a stuck pixel?
A dead pixel is always off, so it shows as a black dot, easiest to see on white. A stuck pixel is always on in one color, easiest to see on black. Stuck pixels can sometimes be fixed; dead pixels usually cannot.
Can dead pixels spread?
A single dead pixel does not spread. If new ones keep appearing, the panel or its connection is failing, which is worth a warranty claim.
Does this dead pixel test work on phones and TVs?
Yes. It works on any screen with a web browser: monitors, laptops, tablets, phones and smart TVs. On an iPhone the test fills the browser window, because iPhone browsers do not allow full screen.
How many dead pixels are acceptable?
It depends on the maker. Many follow ISO 9241-307 pixel classes, allowing a few defects on large panels, while some promise zero dead pixels. Check the warranty terms for your exact model.