TV screen test patterns
Check a TV or monitor for dead pixels, overscan, colour problems and banding. Pick a pattern to fill your screen, or mirror it to the TV first and run the test on the big screen. Nothing to install.
Pick a test pattern
Each pattern opens fullscreen. Click or tap to step through, press Esc to exit. On the dead pixel test, any spot that stays a wrong colour on every screen is a stuck or dead pixel.
Test it on the big screen
Get the Screen Mirroring app
Mirror your phone or computer to the TV with the Screen Mirroring app, then run any pattern here to check the TV itself.
What each test shows
How to read the patterns
Dead pixel test
Solid colours, one at a time. A dot that stays black on every colour is a dead pixel; one stuck on a colour is a stuck pixel.
Overscan and edges
If the outer frame and all four corners are visible, the TV is not cropping the picture. If edges are cut off, turn off overscan or set the TV picture size to Just Scan / Screen Fit.
Colour bars
Standard bars to judge colour and saturation, and to spot a TV that shifts hue or clips bright colours.
Gradient and sharpness
A smooth gradient reveals banding; the fine grid shows whether the panel resolves detail cleanly or looks soft.
In short
What this test can and cannot tell you
What it measures: What you see on full-screen patterns: dead or stuck pixels, cropped edges (overscan), colour and saturation, banding and sharpness.
A good result: No dot stays the wrong colour on every pattern, the outer frame and all four corners are visible, and the gradient looks smooth.
What it cannot tell you: Sound, input lag or HDR. A mirrored picture is compressed, so judge fine sharpness in the TV's own browser rather than through a mirror.