---
title: "Dead Pixel Test & Stuck Pixel Exerciser | Flicker Button"
description: "Check any screen for dead, stuck and hot pixels with full-screen colours, then try the stuck pixel exerciser. Free, in your browser, nothing to install."
url: https://flickerbutton.click/
---

01Screen test

# Dead pixel test

Fill the whole screen with one colour at a time and look for any dot that does not match. Works on any screen with a browser.

## How to run the test

Wipe the screen with a dry microfibre cloth first: a speck of dust looks exactly like a dead pixel until it moves. Set the brightness to where you normally use it, start the full-screen test and step through every colour. Scan the screen in sections from your usual seat, then look closer at anything odd. Black shows pixels that are lit when they should be off; white and grey show pixels that stay dark; red, green and blue test each subpixel on its own.

## Dead, stuck or hot?

- **Dead pixel:** black on every colour. The pixel no longer switches on, and it rarely comes back.
- **Stuck pixel:** a red, green, blue or mixed dot that is brightest on black. One or two of its subpixels stay on. These sometimes recover.
- **Hot pixel:** white on every colour, because all three subpixels stay on.

A dot that changes or disappears when you tilt your head is more likely dust or a mark on the surface than a faulty pixel.

## Trying the exerciser

The exerciser only makes sense for stuck pixels. Move the square over the dot, run it for 10 to 20 minutes, then check again on black and on the dot's colour. Some stuck pixels recover, many do not, and a dead pixel will not. If a new screen has a fault, note where it is and contact the seller while you can still return it: makers' pixel policies differ in how many faulty pixels they accept.

## Sources

- W3C, [Web Content Accessibility Guidelines 2.2, Success Criterion 2.3.1 Three Flashes or Below Threshold](https://www.w3.org/TR/WCAG22/#three-flashes-or-below-threshold), and its definition of [general flash and red flash thresholds](https://www.w3.org/TR/WCAG22/#dfn-general-flash-and-red-flash-thresholds): the 341 × 256 pixel estimate of a 10° field of view and the 25% area limit that the exerciser's square sizes stay under.

## More test channels

Screens, keyboards, mice and controllers.

- [Screen uniformity](https://flickerbutton.click/screen-uniformity-test/): Black and grey levels to show backlight bleed, IPS glow, clouding and dark corners.
- [Keyboard tester](https://flickerbutton.click/keyboard-tester/): Every key on an ANSI, ISO or Mac board, with key codes, rollover and chatter detection.
- [Mouse tester](https://flickerbutton.click/mouse-tester/): All five buttons, accidental double-clicks, wheel steps and a polling rate estimate.
- [Refresh rate test](https://flickerbutton.click/refresh-rate-test/): Your screen's real frame rate, a frame-time graph and moving-block and frame-skip checks.
- [Gamepad tester](https://flickerbutton.click/gamepad-tester/): Buttons, triggers and sticks with a dead-zone view, stick drift check and rumble test.

## Recommended

Two free services for the rest of your setup.

Disposable email · no sign-up

### CleanTempMail

Hardware giveaways, price-drop alerts and the forum where someone fixed your exact keyboard all want an email address first. CleanTempMail gives you a free temporary inbox straight away, with a random or custom address on hundreds of domains, and deletes the messages after 3 days.

Keep your real address for warranty registrations and receipts.

[Open a temporary inbox](https://cleantempmail.com/)

Disposable cloud browser · network checks

### WebTraceCheck

Setting up a new machine? WebTraceCheck's free tools check your connection's IPv4, IPv6, DNS and WebRTC details and whether your browser supports WebGPU. Its disposable cloud browser runs Chrome, Firefox, Edge, Brave or Chromium on an isolated Linux desktop that is deleted after each session.

Nothing to install, with free time every day.

[Try WebTraceCheck](https://webtracecheck.com/)

## Questions

**Can a dead pixel be fixed?**

Usually not. A pixel that stays black on every colour has stopped switching, and software cannot change that. Stuck pixels are different: some recover after a session with the exerciser, or on their own after a few days of normal use.

**Why does the test go full screen?**

So the browser's bars and your taskbar do not hide pixels along the edges. Where a browser cannot make a page full screen, as on iPhone, the test fills the browser window instead: check the strip under the address bar separately, for example by turning the phone round.

**Should I press on a stuck pixel?**

We would not. Some guides suggest pressing on the spot through a cloth, but pressing on a panel can damage it and leave a bigger mark than the one you started with. If the exerciser does not help and the screen is new, use the seller's returns or the warranty instead.

**Do I need to test every colour?**

Black and white catch most faults, and they take a few seconds. Red, green and blue matter when you see a coloured dot and want to know which subpixel is at fault, and grey is the easiest way to spot dim patches and smudges.