Dead Pixel Test
Clean the screen, start the test and look closely at each color. A tiny dot that doesn't match the color is a faulty pixel.
How to check
- Wipe the screen so dust isn't mistaken for a bad pixel.
- Set brightness high and look at the screen straight on, close up, section by section.
- On black, look for dots that glow (stuck or “hot” pixels). On white, red, green and blue, look for black dots (dead pixels) or dots of the wrong color.
Pixel policies
Faulty pixels on a new screen aren't always covered by warranty. Many manufacturers base their policy on the old ISO 13406-2 “Class II”, which allowed a few faulty pixels per million. Check your brand's pixel policy and test while the shop's return window is still open.
Frequently asked questions
What's the difference between a dead and a stuck pixel?
A dead pixel stays black on every color because it gets no power. A stuck pixel stays lit in one color (red, green, blue or white). Stuck pixels sometimes recover; dead pixels usually don't.
When should I test a new monitor?
Right after unboxing, while you can still return it. Many manufacturers only replace screens with several faulty pixels, but a shop's return window often has no such limit.
Can I test my phone or TV?
Yes. Open this page on the device and start the test. On iPhone the page fills the browser window instead of going truly full screen; turn the phone sideways and hide the toolbar by scrolling for the best view.