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Dead Pixel Test

Cycle solid fills to spot stuck or dead subpixels.

Press F for fullscreen
Controls
Current · #ffffff

Arrow keys to switch colors. Look for unchanging pixels.

About Dead Pixel Test

A dead pixel is a single subpixel that has failed and shows up as a black, white, or stuck-color speck on a uniform fill. The dead-pixel test cycles the panel through pure white, black, red, green, blue, and the three secondaries. Any pixel that does not match its neighbors is a candidate. Use this tool when verifying a new monitor before the return window closes, or to check a panel after shipping damage. It also helps confirm that you have not just been looking at a dust mote.

New Monitor Quality Check Before Return Window

Run the dead pixel test on every new monitor before the retailer's return window closes. The tool cycles through pure white, black, red, green, blue, and secondary fills — any pixel that does not match its neighbors across all fills is defective. Check within the first 48 hours of delivery while the exchange policy is active. Inspect at arm's length first, then move closer to spot sub-pixel defects. New monitors from every manufacturer occasionally ship with dead or stuck pixels, and most retailers accept returns only if defects are documented early. Take a screenshot of any anomalies as evidence for your return claim.

Stuck Pixel vs Dead Pixel Identification

A stuck pixel shows a constant color across every fill — it is receiving signal but the subpixel is locked. A dead pixel shows black on every fill because the transistor has failed completely. The auto-cycle mode reveals both types: stuck pixels stand out as a fixed color dot that does not change with the background, while dead pixels appear as a persistent black speck on bright fills. Stuck pixels can sometimes be revived by rapid color cycling (see the burn-in fixer tool), but dead pixels are permanent hardware failures. Knowing the difference determines whether you attempt a fix or initiate a warranty claim.

Shipping Damage and Panel Stress Testing

After any monitor arrives via shipping, the dead pixel test reveals pressure damage from handling. A cluster of dead pixels in one area often indicates impact damage rather than a manufacturing defect. Run the full color cycle and pay special attention to the corners and center of the panel, which are most vulnerable to shipping stress. Document any anomalies with photos before contacting the retailer. The test also serves as a regular panel health check — run it monthly to catch pixels that fail over time due to thermal stress or aging components.

How to use it

  1. 01

    Go fullscreen

    Press F so no browser chrome distracts.

  2. 02

    Step through the colors

    Use the arrow keys or click a swatch in the controls panel. Auto-cycle is optional — tick the checkbox to let it advance every 1.8 seconds.

  3. 03

    Inspect closely

    Sit close enough to the panel that a single pixel is visible. Look for points that stay one color across every fill.

  4. 04

    Download the current view as a PNG

    Click the download icon in the top-right toolbar — it sits between the settings gear and the fullscreen button. We detect your display's physical pixel count (screen resolution × device pixel ratio) and rasterize the current configuration into a Retina-sharp PNG. The file lands in your browser's default downloads folder; to save straight to the Desktop, enable 'Ask where to save each file' in your browser settings. The filename includes the resolution so you can keep multiple variants side by side.

Frequently asked

The shortest path between you and the answer.

Stuck pixel vs dead pixel?

A stuck pixel still receives signal and shows a constant color. A dead one shows black on every fill. The same auto-cycle reveals both.

Can I fix a stuck pixel from a browser tab?

Sometimes. A rapidly flashing test (the burn-in fixer tool) can re-seat a stuck subpixel by exercising it. There is no software fix for a truly dead one.

Is this tool free?

Yes. Every ScreenTools.co tool is free, with no account, no paywall, and no install.

Does it work on mobile?

Yes. Layouts adapt to phone and tablet screens. Mobile Safari restricts true fullscreen, but the page fills the viewport and you can add the page to your Home Screen for an app-like experience.

Does it work offline?

Once a tool's page has loaded once, the runtime is local. A few tools that fetch fonts or icons need the first hit online; after that, refresh works offline.

Does this collect my data?

No personal data leaves your browser. The site has lightweight, privacy-respecting analytics for aggregate counts (which tool was opened) and nothing else.

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