How to use this tool
- 1Tap a color or the 'Start full-screen test' button.
- 2With the screen filled, tap to cycle red, green, blue, white, black and gray.
- 3Look closely: fixed black dots are dead pixels; dots stuck on one color are stuck pixels.
- 4Permanent shadows or ghost images on AMOLED screens indicate burn-in.
- 5Press ESC (or the system back gesture) to exit full-screen.
About this test
The dead pixel test displays pure colors across the whole screen to reveal defects you never notice in daily use. On a red background, for example, a burned sub-pixel shows up as a tiny black or off-color dot.
Run this test before buying a used phone or right after receiving a new one, while you can still claim warranty. Some stuck pixels can be recovered by rapidly cycling colors for a few minutes.
Privacy: this tool runs entirely in your browser. No image, audio or device data is recorded or sent to any server.
Frequently asked questions
What is the difference between a dead pixel and a stuck pixel?
A dead pixel stays permanently off (black) because it gets no power, while a stuck pixel is frozen on one color (red, green or blue). Stuck pixels sometimes recover; dead pixels usually don't.
Can this test damage my screen?
No. It only displays static colors for a short time, which is completely safe for any LCD or OLED display.
Do I need to install an app?
No. The test runs 100% in your phone's browser, with nothing to download and no data sent to any server.