Dead pixel test
Find dead or stuck pixels on your monitor, laptop, TV or phone screen with full-screen colors.
How to useLook for dead pixels.
Opens in full screen. Click, tap or use the arrow keys to change color; Esc to exit.
Available in: 
Dead pixel test: what it is for
The test fills the whole screen with pure colors, such as black, white, red, green and blue, to reveal pixels that don't light up or are stuck on one color. There is also a mode that flashes the colors, which sometimes unsticks stuck pixels.
It's ideal for checking a new or used monitor or phone.
How to use
- Click start in full screen.
- Change colors by clicking or with the arrow keys.
- Look for dots of a different color.
When to use it
- Checking a monitor or TV when buying.
- Used phone or laptop.
- Within the return period.
Frequently asked questions
How do I know if I have a dead pixel?
On each color, look for a tiny dot that doesn't change. A black dot on a white background is a dead pixel; a colored dot on a black background is a stuck pixel.
Can a stuck pixel be fixed?
Sometimes. Use the “flash colors” mode over the area for 10 to 20 minutes. A dead pixel (always black) usually doesn't come back.
Is it worth using when buying a monitor or phone?
Definitely. Run the test as soon as you receive the device, while you are still within the return period.
Is it really free?
Yes, 100% free. No sign-up, no subscription and no usage limits. All Tools123 are free.