Screen Test
Fullscreen colors, dead & stuck pixel checks, banding and a drawing whiteboard. Runs entirely in your browser.
How to test your screen
A screen test shows pure fullscreen colors and gradients so you can spot hardware defects the eye normally misses. Use it before you buy a used monitor, after shipping, or any time a panel looks off. Everything below runs in your browser, free, on any device.
1 · Find dead and stuck pixels
Open the Dead Pixel Test and step through the solid colors (tap, click, or swipe right). A dead pixel stays black on every color; a stuck pixel holds a fixed red, green or blue dot. Pure red, green, blue, white and black reveal both most clearly.
2 · Try the stuck-pixel fixer
The Stuck Pixel Fixer cycles colors rapidly for 10–30 minutes. It can sometimes recover a stuck sub-pixel; it cannot revive a dead one. It is free and harmless, so worth a try before a warranty claim.
3 · Check color & banding
The Gradient & Banding test shows smooth ramps. Visible steps instead of a clean gradient point to banding, often the mark of a 6- or 8-bit panel versus a 10-bit one. Relevant for color theory, photography, video and design, where color accuracy matters.
4 · Draw and annotate
Need to mark a spot or write on the test? Open the Whiteboard, draw freehand, drop text and images, then right-click for tools and quick colors. Handy for showing a seller exactly which pixel is dead.
Why color accuracy matters
Monitors render color differently, and a single panel drifts over time. Photographers and video editors calibrate so the colors they see match the final output; designers check that a brand red looks the same across screens. A quick screen test is the first step, before any color management or hardware calibration with a colorimeter.