Dead Pixel & Screen Test
Fill your screen with solid colours to spot dead or stuck pixels, uneven brightness and burn-in.
How to use
- 1Clean your screen so dust isn't mistaken for a pixel.
- 2Tap Start test to go full-screen.
- 3Tap the screen (or press the arrow keys) to change colour.
- 4Look closely for dots that don't match the colour around them.
- 5Press Esc or tap Exit to finish.
Dead pixels vs stuck pixels
A dead pixel stays black on every colour because it isn't receiving power. A stuck pixel stays one colour — often red, green or blue — because one sub-pixel is always on. Stuck pixels are sometimes temporary; dead pixels rarely recover.
What to look for on each colour
Black
Bright dots are stuck pixels. On LCD screens, glowing edges are backlight bleed. OLED screens should look completely black.
White
Dark dots are dead pixels. Look for yellowish patches or uneven tint.
Red, green and blue
A dot that's a different colour reveals a stuck sub-pixel.
Grey
Mid-grey is the best colour for spotting burn-in — faint ghosts of keyboards, navigation bars or status icons.
Checking a used or new phone
If you're buying a second-hand phone, run this test before paying. For a new phone, check within the return window; manufacturers and retailers each have their own policies on how many defective pixels count as a fault.
Can stuck pixels be fixed?
Sometimes. Rapidly flashing colours over the area for a while may unstick a pixel, but results vary and there's no guarantee. Never press hard on the screen. Dead pixels and burn-in usually need a screen replacement.
Helpful products
Affiliate links — we may earn a commission.
- Microfibre screen cleaning kit
Clean the screen first so dust isn't mistaken for a dead pixel.
- Tempered glass screen protector
Protects the display from scratches and cracks.
Frequently asked questions
How do I exit full-screen?
Tap the Exit button, press Esc on a keyboard, or swipe from the edge on mobile.
Why doesn't full-screen work on my iPhone?
iPhone Safari limits the Fullscreen API. The test still fills the browser window; hide the toolbars by scrolling or rotating for the best view.
How many dead pixels are acceptable?
It depends on the manufacturer's policy. Many treat even one clearly visible dead pixel on a phone as a defect, but check your warranty.
Is a dot on the screen always a dead pixel?
No — clean the screen first. Dust under a screen protector can look like a pixel defect.
Can this test detect burn-in?
Yes, use the grey screen and look for faint shapes of static UI elements.
Does the test harm my screen?
No. It just displays solid colours, like any image.
Related tools
Touch Screen Test
Swipe over a full-screen grid to find unresponsive areas and count touch points.
Speaker & Stereo Test
Play sound from the left, right or both speakers and check frequency response.
Vibration Test
Check your vibration motor with short, long and pattern buzzes.