GearCheckHow to run a dead pixel test
- Clean the screen with a dry microfiber cloth — dust looks exactly like a dead pixel.
- Start the full-screen test. Click or press Space to move through black, white, red, green, blue and more.
- Scan the whole screen on each color, section by section. Corners and edges are easy to miss.
- Note the color of any bad pixel; it tells you what kind of defect it is (see the table).
What you might find
| You see | Defect | Fixable? |
|---|---|---|
| Black dot on white or colored backgrounds | Dead pixel | Rarely |
| Red, green or blue dot on black | Stuck pixel | Often, with the fixer |
| White dot on black | Hot pixel | Sometimes |
| Glow from the edges on black | Backlight bleed (LCD) | No — normal in small amounts |
| Visible steps in the gradient | Color banding | Check color depth and settings |
How the stuck pixel fixer works
Every pixel is made of red, green and blue sub-pixels controlled by liquid crystals (LCD) or tiny diodes (OLED). A stuck sub-pixel is sometimes just a crystal that won't change state. Flashing rapidly changing colors over it forces it to switch thousands of times, which can free it. Place the flashing square over the pixel, leave it running for 10–30 minutes, and check again. If nothing changes after an hour, the pixel is unlikely to recover.
Important: the fixer flashes very quickly. Don't use it if you're sensitive to flashing light, and look away while it runs.
Testing a new monitor or TV
Run this test as soon as you unbox a new screen — return windows are often only 14–30 days, while manufacturer pixel policies can be strict about how many bad pixels qualify for a replacement. While you're at it, check that a high refresh rate monitor actually runs at its rated speed with the refresh rate test, and confirm the resolution with what is my screen resolution. On a touch display, also run the touch screen test.
Frequently asked questions
How do I check for dead pixels?
Clean the screen, press Start full-screen test and look closely at each solid color. On black, look for dots that stay lit; on white, red, green and blue, look for dots that stay dark or show the wrong color. Use a magnifying glass or your phone’s camera zoom for high-resolution screens.
What is the difference between a dead and a stuck pixel?
A dead pixel is always black because it gets no power — it stands out on white. A stuck pixel is always one color (red, green, blue or a mix) because one or more of its sub-pixels is permanently on — it stands out on black. A “hot” pixel is always white.
Can a stuck pixel be fixed?
Sometimes. Running the stuck pixel fixer over it for 10–30 minutes, or gently massaging the spot with a soft cloth while the screen is off, revives some stuck pixels. Dead pixels (always black) can almost never be fixed by software.
How many dead pixels are acceptable?
It depends on the manufacturer’s pixel policy. Many follow ISO 9241-307 class II, which allows a small number of defective pixels; some brands offer “zero bright dot” guarantees. Test a new screen right away so you can return it within the store’s return window.
Does this work on phones, TVs and laptops?
Yes — any screen with a browser. On a phone, tap to change colors and swipe right to go back. For a TV, open this page in the TV’s browser or cast a full-screen tab from a computer.