Dead Pixel Test

Fill your screen with pure colors, gradients and moving bars so single dead or stuck pixels stand out against a flat field.

The test only paints colors on your screen. No camera, no microphone, no storage, no network — nothing to leak.

Mode:

Tap or press any key to advance · press 1–8 to jump to a color · press Esc to exit

How It Works

A bad pixel is invisible in ordinary content and obvious on a flat field, so the test paints pure colors across your whole display: eight solids (white, black, red, green, blue, yellow, cyan, magenta) held for three seconds each, or a sweep mode with a scrolling full-spectrum gradient and moving black bars. Any single dot that disagrees with its background pops out at a glance — press keys 1 to 8 during solid mode to jump straight to a color, and tap or press any key to advance early.

Reading the result: dead vs stuck
A dead (dark) pixel never lights: it is a black dot on the white screens and invisible on black. A stuck pixel is one sub-pixel pinned on: bright red, green or blue on white? It blends in; that same colored dot on a black screen is a stuck pixel. A dim or discolored patch spread over many pixels is backlight or pressure damage, not a pixel defect — worth noting in a claim either way.
Where and how to look
View the screen at normal arm's length in a dimmed room with the screen clean — a speck of dust looks exactly like a dead pixel up close. Scan in a slow grid, and use the moving-bar sweep to spot clusters. When you think you found one, mark the spot (tape flag or screenshot with the colored screen visible) before restarting the test to confirm it is in the same pixel location.
On phones and tablets
The same test works: start it in the mobile browser, rotate to whichever orientation fills the screen, tap to advance through the colors and hold the phone still at arm's length, or prop it up and walk slowly around it. OLED phones can show a permanently dim dot instead of a black one — that is still a failing sub-pixel.

Frequently Asked Questions

Can a dead pixel come back?

A truly dead sub-pixel (always black, on every color) usually stays that way — the transistor or connection has failed. A stuck pixel (always red, green or blue) is a sub-pixel pinned at full brightness, and some of those do free themselves over time or with the moving-bar mode gently running for a while. Nothing here promises a repair, and pressing hard on the panel is best left alone — it fixes some panels and cracks others.

Will the manufacturer replace my screen for one bad pixel?

Depends on the warranty terms, not on the count alone. Flat panels are sold under defect classes (the ISO 9241-307 family and manufacturer policies), and many consumer warranties tolerate a small number of defects depending on type and position — a single dead pixel in the center often qualifies, one in the corner may not. Check your brand's pixel policy before opening a claim, and take photos on each solid color as evidence.

Can I also test my webcam or microphone here?

No — this page only paints colors. Camera and microphone checks live on a separate tool, the Camera & Mic Test, which walks through permissions, device pickers and a level meter.

How often should I run the test?

There is no maintenance schedule — run it when you suspect something (after a transport, a drop, or when a new speck shows up in the same spot across every image). A quick 25-second sweep is enough; most new 'dead' spots turn out to be dust on the glass, so clean the screen first.

Is anything uploaded to a server?

No. The test draws colors with a local canvas and CSS — no network request, no storage, no permission of any kind. Once the page is loaded it works fully offline, including full screen.