Screen Test
Tap a color to fill your whole screen with it. Look closely for dead pixels (always black), stuck pixels (always one color), or backlight bleed on dark colors.
Choose a test color
Tap any swatch to go fullscreen. Tap anywhere for mobile, press Escape for desktop, to exit.
How to use the screen test
Tap any color swatch to fill your entire screen with that color. Look closely, corner to corner, for any spot that doesn't match — a permanently black dot on a white screen (a dead pixel), a spot that stays one color regardless of the background (a stuck pixel), or patches of uneven brightness on dark colors (backlight bleed). Cycle through several colors, especially black and white.
Why test your screen
Dead and stuck pixels are often invisible during normal use — buried in busy images or video — but become obvious the moment you view a single solid color. This test is most useful right after unboxing a new monitor, phone, or laptop, or when buying a used device.
Understanding what you're seeing
- Dead pixel: stays black no matter what color fills the screen — the pixel isn't receiving any power.
- Stuck pixel: shows a fixed color regardless of what's displayed — sometimes fixable with pressure or software flickering techniques, unlike dead pixels.
- Backlight bleed: patches of lighter gray visible mainly on a black screen, usually around the edges — common on LCD panels and generally not a defect worth returning a device over unless severe.
Frequently asked questions
How many dead pixels are considered normal?
Most manufacturers consider a small number within acceptable tolerance — check your specific manufacturer's dead pixel policy if you're considering a return.
Can a stuck pixel be fixed?
Sometimes — gentle pressure on the area or pixel-cycling software that rapidly flashes colors can occasionally unstick it, though this isn't guaranteed.
Does this test work on phone screens?
Yes — open this page in your phone's browser and tap a swatch to fill the screen the same way as on a monitor.