What is it?
The Dead Pixel Test helps you find faulty dots on a screen. It fills the screen with plain colours and patterns so dead or stuck pixels stand out, and it also measures the refresh rate.
Who is it for?
People buying a new monitor, TV, laptop or phone (check before the return window ends), buyers of second-hand devices, and gamers.
How to use it
- Clean the screen first. Tap ▶ Start full-screen test.
- Look closely at each colour; tap to move to the next.
- Tap Measure refresh rate (keep this tab in front and do not scroll).
Returns and warranty
Many brands allow a few dead pixels under warranty. Test on the day of purchase and photograph any defect for the seller.
Errors and how to fix them
- Black dot on all colours: a dead pixel; usually permanent.
- Coloured dot that stays one colour: a stuck pixel; it may fix itself or with gentle pressure through a soft cloth.
- Refresh rate lower than advertised: check display settings and the cable (HDMI versions limit high refresh rates).
Questions people ask
- How long should I look at each colour? A few seconds each, scanning the whole screen up close.
- Does it work on phones? Yes, in full screen.
Practical tip
Check the screen in a dark room at full brightness; stuck and dead pixels are easiest to see on pure black and pure white.
Open the tool: Dead Pixel Test
Still stuck?
Contact support. Tell us which tool or page you were using, what you tapped, what you saw, and your phone or computer and browser (for example: Android phone, Chrome). We reply by email.
Questions, or an error not listed here?
Tell us in the comments: what you were doing, the exact message you saw, and your device and browser. We read every comment and add new fixes to this article.