Full-screen color test · Auto-cycle timer · Grid overlay for precise location · 8 test colors. No download.
This tool fills your entire screen with solid colors to reveal dead, stuck, or hot pixels that would otherwise be hidden by normal screen content. By cycling through black, white, red, green, blue, and other colors in full-screen mode, individual defective pixels become clearly visible against the uniform background.
Click Fullscreen Test to fill the entire display with one solid color, then scan slowly across it — any pixel that doesn't match the background is dead or stuck. Turn on Auto-Cycle to step through all 8 colors at a set interval hands-free, and enable the Grid Overlay to pinpoint the exact location of a defect for a warranty claim.
A dead pixel is always black (all subpixels off — transistor failure). A stuck pixel is always one color like red, green, or blue (one subpixel stuck on). Stuck pixels are often fixable; dead pixels usually are not.
White reveals dead (black) pixels. Black reveals hot (white) pixels. Red reveals missing red subpixels (appear dark on red). Use all colors systematically — some defects only appear on specific color backgrounds.
Industry standard ISO 13406-2 Class II allows up to 2 dead pixels per million. Premium monitors (Dell UltraSharp, etc.) offer zero dead pixel guarantees. Most budget panels allow 5+ dead pixels before warranty replacement.
True dead pixels (black) are usually permanent. Stuck pixels (colored) can sometimes be fixed by rapidly cycling colors or applying gentle pressure. Leave the cycling test running for 1–2 hours for best results.
Click the "Full Screen" button on the test panel. On mobile, the button activates full-screen mode. On iOS Safari, use the "Add to Home Screen" option for a better full-screen experience, as Safari has limited full-screen API support.
Bright spots that appear blurry or larger than one pixel are likely pressure damage or IPS glow — a common phenomenon in IPS panels where backlight bleeds slightly at the corners or edges. This is a backlight issue, not a pixel defect.
Contact your device manufacturer or retailer while under warranty. Document the pixels using the grid overlay to record exact positions. Check your warranty policy — coverage varies from zero dead pixel guarantees to requiring 5+ pixels for replacement.
ISO 13406-2 defines display quality classes. Class I allows zero defective pixels. Class II (most consumer displays) allows up to 2 type 1 defects (permanently lit white pixels). Most premium brands (Apple, Samsung OLED) guarantee zero defective pixels. Check your manufacturer's dead pixel policy before purchase.
Yes. Open this page in your mobile browser and tap Fullscreen Test. The color controls appear at the bottom. Swipe your finger slowly across the screen while looking for anomalous pixels.
The grid divides the screen into a reference grid so you can precisely identify where a defective pixel is located (e.g. "third row, second column from the right"). This is useful when reporting a defect to a manufacturer for warranty replacement.