Dead Pixel Test
Fill your screen with solid colors and spot dead or stuck pixels in seconds.
The test fills your entire screen with solid colors. Look for dots that don't match.
Click / any key = next color · Esc = exit
How to run the dead pixel test
- Clean your screen first — dust specks are the #1 cause of false alarms.
- Click Start Full-Screen Test. Your screen fills with solid black.
- Scan the whole screen slowly, then click (or press any key) to move to white, red, green, and blue.
- Any dot that stays the wrong color on one or more screens is a defective pixel. Press Esc when done.
Why each color matters
Every pixel on your screen is made of red, green, and blue sub-pixels. A black screen exposes stuck sub-pixels (bright dots), while a white screen exposes dead pixels (dark dots). The red, green, and blue screens isolate each sub-pixel so you can tell exactly which one has failed — useful information for a warranty claim. Just bought a new monitor? Run this test on day one, while an exchange is still easy. While you're at it, check your keyboard and mouse too.
Frequently Asked Questions
How do I check my screen for dead pixels?
Start the test to fill your screen with a solid color, then look closely for any dot that stays a different color. Click or press any key to cycle through black, white, red, green, and blue — a defective pixel will stand out on at least one of them. Press Esc to exit.
What is the difference between a dead pixel and a stuck pixel?
A dead pixel gets no power and shows black on every color. A stuck pixel is frozen on one color (often red, green, or blue) because one of its sub-pixels stays on. Stuck pixels can sometimes recover; dead pixels usually cannot.
Can a stuck pixel be fixed?
Sometimes. Rapidly cycling colors in the stuck area for 10–30 minutes can nudge a stuck sub-pixel back to life, and some people gently massage the spot with a soft cloth while the screen is on (at your own risk). Dead pixels — fully black ones — are physical failures and cannot be fixed by software.
How many dead pixels are acceptable for a warranty claim?
It varies by manufacturer. Many follow ISO 9241-307 class definitions where a handful of defective pixels is considered "within spec" — but premium panels are often sold with zero-dead-pixel guarantees. Check your manufacturer’s pixel policy and run this test within the return window of any new monitor.
Does this test work on phones and TVs?
Yes — it runs in any browser. For TVs, open this page in the TV browser or cast it. On phones, rotate through the colors and inspect the screen up close; OLED phone screens show dead pixels most clearly on white.