How to use
- Clean the screen so dust is not mistaken for a pixel fault.
- Click a colour to fill the screen.
- Click, press Space or use the arrow keys to move through the colours; press Esc to finish.
- Look closely for dots that do not change colour.
Options explained
- Dead pixel
- Stays black on every colour. Most visible on the white screen.
- Stuck pixel
- Stays red, green or blue. Most visible on the black screen, and sometimes recoverable by rapidly flashing colours.
- Backlight bleed
- Uneven bright patches near the edges, visible on the black screen in a dark room.
What each colour reveals
A pixel is made of red, green and blue subpixels. Each test colour switches different subpixels on or off, so a fault shows up against the right one:
| Colour | Hex | Look for |
|---|---|---|
| Black | #000000 | Pixels that stay lit (stuck on), and backlight bleed at the edges |
| White | #ffffff | Dark dots, which are dead pixels or dust |
| Red | #ff0000 | Dots of another colour or black, meaning a faulty red subpixel |
| Green | #00ff00 | The same for the green subpixel |
| Blue | #0000ff | The same for the blue subpixel |
| Gray | #808080 | Uneven brightness and banding across the panel |
A dot that shows on only one colour usually means a single faulty subpixel. A dot that is wrong on every colour is a fully dead or stuck pixel. Check from a normal viewing distance first, then up close.
Frequently asked questions
How do I report a dead pixel under warranty?
Take a photo of the screen showing the fault on a solid colour, note its position, and check your manufacturer's pixel policy; many allow a small number of faulty pixels.
Can a stuck pixel be fixed?
Sometimes. Turning on auto cycling for a while, or gently pressing the spot with a soft cloth while the screen is off, can free a stuck subpixel. Dead pixels usually cannot be fixed.
Does it work on phones?
Yes. Colours fill the viewport, and on devices that allow it the page switches to full screen.
Privacy
This tool runs entirely in your browser. Your files and text are processed on your device and are never uploaded to our servers.