Dead Pixel Test
Fullscreen color cycle to find dead, stuck, and bright pixels on any monitor, laptop, phone, or tablet screen. Cycles through red, green, blue, white, black, and gray — the pattern that reveals every type of pixel defect.
Ready to test your screen?
The test cycles through 6 solid colors (red, green, blue, white, black, gray). Any pixel that does not blend with the background is defective — bright dots on color, dark dots on white, glowing dots on black.
About Dead Pixel Test
A dead pixel is a permanently OFF pixel — visible as a dark dot against a white background. A stuck pixel is stuck ON in one color (usually red, green, or blue) — visible as a bright dot against a differently-colored background. Both are hardware defects that a single-color test screen makes obvious. This dead pixel test cycles through six solid colors (red, green, blue, white, black, gray) in fullscreen mode. Any pixel that does not match the surrounding color is defective, and cycling through all six catches every type of pixel and subpixel failure.
Practical for buyers verifying a new monitor, laptop, phone, or tablet before the return window closes, warranty claims where you need visual proof of defect count, and second-hand purchases where the seller's pictures do not reveal pixel issues. The tool uses the browser fullscreen API where available and falls back to a full-viewport overlay when not — either way, the entire screen fills with the test color for a clean check. Arrow keys, space, or click advance to the next color; H toggles the on-screen hints so you can inspect edges of the screen without an overlay in the way; Esc exits. Do the test in a dim room with a clean screen for best results — dust and smudges can look like defects.
How to Use
Click 'Start test' — the tool goes fullscreen with a solid red screen.
Look closely at the screen for dots that do not match the background color: bright dots on colored backgrounds, dark dots on white, or glowing dots on black.
Press → (right arrow), Space, or click to cycle to the next color. ← (left arrow) goes back. Press H to toggle the on-screen hints.
Press Esc or click Exit at any time to leave the test.
For best results, do the test in a dark room with a clean screen — dust and smudges can look like defects.
Frequently Asked Questions
What is the difference between a dead pixel and a stuck pixel?
A stuck pixel is stuck in an ON state — it displays one color (usually red, green, or blue) permanently. A dead pixel is completely OFF — it appears as a black dot on any background. Stuck pixels can sometimes be fixed with pixel-fixing videos or gentle pressure massage. Dead pixels are usually permanent hardware failure.
Why do I need to test on solid colors?
A single defective subpixel is invisible against most content — you only see it when the surrounding pixels are the opposite color. Solid red exposes stuck-blue and stuck-green pixels; solid white exposes fully-dead pixels; solid black exposes fully-lit ('bright') pixels.
My monitor has a warranty — how many dead pixels qualify for replacement?
Depends on the manufacturer's ISO 13406-2 class rating. Most consumer monitors are Class II — usually allowing up to 2 bright, 2 dark, and 5 subpixel defects before replacement. Premium 'zero-defect' displays cover any dead pixel. Check your manufacturer's specific policy — the tool identifies the defects; you decide whether they qualify.
Can this test fix a stuck pixel?
No — this is a diagnostic tool, not a repair tool. For stuck-pixel fixing, there are dedicated videos that rapidly flash red/green/blue in a small square, encouraging the stuck subpixel to unstick. Success rate is maybe 30-50%. This tool identifies the pixel; a dedicated fixer tool attempts the repair.
Should I test my phone or tablet screen the same way?
Yes — the test works on any screen (laptop, phone, tablet, TV, external monitor). On mobile, tap the screen to cycle colors. The fullscreen API may not go true-fullscreen on iOS, but the color-filled div covers the visible viewport which is enough for the test.