What to look for on each color
| Color | What it reveals |
|---|
| Black | Find stuck pixels (dots that stay lit) and backlight bleed |
| White | Find dead pixels (dots that stay dark) and dirt on the screen |
| Red | Spot pixels with a broken red sub-pixel |
| Green | Spot pixels with a broken green sub-pixel |
| Blue | Spot pixels with a broken blue sub-pixel |
| Cyan | Check combined green and blue |
| Magenta | Check combined red and blue |
| Yellow | Check combined red and green |
| Gray | Check uniformity and dark or bright patches |
Dead pixel vs stuck pixel vs hot pixel
- Dead pixel: always black. Visible on white and bright colors.
- Stuck pixel: always one color (red, green, blue or a mix). Visible on black.
- Hot pixel: always white. Visible on black. This term is also used for camera sensors.
- Dust or a scratch: looks like a dark dot, but moves or disappears when you clean the screen or change your viewing angle.
When to test a screen
- As soon as you unbox a new monitor, laptop, TV or phone, while you can still return it.
- Before buying a used device.
- After a drop or pressure on the screen.
Tips for a thorough check
- Set the screen to its native resolution and turn brightness up.
- Test in a dim room for black screens and a bright room for white screens.
- Scan slowly in rows from one corner to the other, and use a magnifying glass for high-resolution screens.
Check your screen's refresh rate with the refresh rate test, or test your keyboard and controller.
Last reviewed October 2026.
Frequently asked questions
What is a dead pixel?
A dead pixel stays black (or dark) no matter what color is shown, because it receives no power or its transistor has failed. It is easiest to see on the white screen.
What is a stuck pixel?
A stuck pixel is stuck on one color, such as bright red, green or blue, because one or more of its sub-pixels is always on. It shows up best on the black screen. Stuck pixels can sometimes be revived, while dead pixels usually cannot.
How do I use the dead pixel test?
Clean your screen, press Start test to go full screen, then click, tap or press the arrow keys to move through each color. Look closely across the whole screen for dots that do not match. Press Esc to exit.
How can I fix a stuck pixel?
Some people have success by gently massaging the spot with a soft cloth while the screen is off, or by running a pixel-cycling video for a while. These methods do not always work, so if your screen is new, check the return policy or warranty first.
How many dead pixels are acceptable?
It depends on the manufacturer. Many have a "pixel policy" that only covers a screen when there are several defective pixels or one in the center. Check your monitor's or laptop's warranty terms, and test new screens within the return window.
What is backlight bleed?
Backlight bleed is light leaking around the edges of an LCD screen, seen as brighter patches on a black image in a dark room. A little is common. OLED screens do not have backlight bleed.