Question 1

Is this dead pixel test free?

Accepted Answer

Yes, and it always will be. There's no sign-up, no time limit, and no catch — click "Start fullscreen test" and you're testing within a second.

Question 2

Do I need to download or install anything?

Accepted Answer

No. Everything runs in this browser tab, so there's nothing to install and nothing left behind when you close it.

Question 3

Does this tool read or upload anything from my screen or device?

Accepted Answer

No. This tool only displays colors — it never reads anything about your device, and it doesn't even have a server to upload to. Nothing is recorded, transmitted, or stored anywhere.

Question 4

What's the difference between a dead pixel and a stuck pixel?

Accepted Answer

A dead pixel never lights up at all, so it shows as a small black dot against any color. A stuck pixel is locked showing one color, usually red, green, or blue, no matter what's behind it. A "hot" pixel is a stuck pixel that's locked fully bright or white.

Question 5

How do I check my screen for dead pixels with this tool?

Accepted Answer

Cycle through the colors with the Next/Previous buttons, and watch closely for any dot that doesn't match what's on screen. Spot one, and click or tap that exact point to mark it.

Question 6

Can this tool automatically detect dead pixels for me?

Accepted Answer

No, and no online tool actually can — a monitor's physical pixel state isn't something a browser or website can read, unlike a keystroke or a microphone signal. What this tool does instead is give you a clean way to look and a structured place to record exactly what you personally see.

Question 7

What does clicking or tapping on the screen do?

Accepted Answer

It drops a marker at that exact spot, tagged with whichever color was on screen at that moment, and adds it to your report below the color area.

Question 8

Is my report saved anywhere?

Accepted Answer

No — it only exists in this browser tab for as long as you keep it open, and it's gone the moment you leave the page. Use "Copy report" or "Download report" first if you want to keep it, for example before a return-window deadline.

Question 9

What formats can I export my report in?

Accepted Answer

Three, all downloading immediately from the "Download report" menu: plain text, CSV (opens straight in a spreadsheet), and JSON (for pulling into another tool).

Question 10

Why does this test ask me to go fullscreen first?

Accepted Answer

A dead or stuck pixel is easiest to catch at your screen's actual physical size, edge to edge — a small preview box on the page can't show that. Click "Start fullscreen test" and your browser's toolbar and tabs disappear completely; click "Finish" or press Esc to exit fullscreen whenever you're done, without losing what you've already marked.

Question 11

Does fullscreen work on every device?

Accepted Answer

Most desktop and Android browsers support it. Some browsers, notably Safari on iPhone and iPad, don't support true fullscreen for a page like this one. The color test still works exactly the same without it — your browser's own toolbar just stays visible.

Question 12

Does this work on mobile?

Accepted Answer

Yes. Tap through colors with the on-screen buttons and tap anywhere on the screen to mark a spot. Phone and tablet screens can have dead or stuck pixels too, especially on a secondhand device.

Question 13

Why does this test use more than just red, green, blue, black, and white?

Accepted Answer

It also cycles through cyan, magenta, yellow, and gray. A defect in a single sub-pixel can be nearly invisible against a pure primary color, since the pixel can still look roughly right, but the same defect shows up clearly as an off-hue tint against a color that mixes two channels, or against mid-gray.

Question 14

Can I use this to check a screen before a return-window deadline?

Accepted Answer

Yes. Copy or download your report as you go, so you have a clear, timestamped record of exactly what you found and where, whether that's for a return, a warranty claim, or just showing a seller.

Dead Pixel Test

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