Dead Pixel Test

If a colored dot, dark speck, or bright fleck won't go away no matter what's on screen, you're probably looking at a dead, stuck, or hot pixel. The fastest way to know for sure is to cycle your display through solid colors that strip away camouflage and make panel flaws stand out. This free tool fills your screen with nine solid colors plus a grayscale sweep in under two minutes, and it runs entirely in your browser: nothing you see is ever recorded or sent anywhere.

Runs entirely in your browser — nothing is uploaded

Opens in fullscreen

How it works

Open the Test in Fullscreen. Launch the test and click or tap to start; your browser switches to true fullscreen (press F11 on desktop if it doesn't happen automatically). Clean the screen and dim the room first for the most accurate read.
Cycle Through Each Solid Color. Advance through black, white, red, green, blue, cyan, magenta, yellow, and 50% gray using a click, tap, arrow key, or swipe. Each fill isolates a different type of pixel fault.
Inspect Each Fill Closely. On every color, scan the whole panel methodically, including corners and edges, for any dot, speck, or fleck that doesn't match the surrounding color.
Watch the Grayscale Gradient. Let the smooth black-to-white sweep play and look for visible banding or patchy brightness, which points to color banding or uneven backlight rather than a single dead pixel.
Note the Position of Any Flaw. If something looks off, note which color revealed it and roughly where it sits, then cycle back to confirm it appears in the same spot on a second pass.
Exit Fullscreen. Press Esc, or tap the corner exit button on touchscreens, to leave fullscreen and return to the page.

How the Test Works: What Each Color Reveals

A pixel is really three subpixels, red, green, and blue, working together. A single failed subpixel hides easily in normal content, so this test uses flat, full-screen colors chosen to expose one type of failure each, rather than one generic pattern.

Black exposes stuck-on or hot subpixels: any glow of red, green, blue, or white against pure black shouldn't be there.
White exposes dead (dark) subpixels, plus scratches and dust invisible on busy content.
Red, green, and blue isolate each color channel individually.
Cyan, magenta, and yellow catch partial failures and confirm what the primaries showed.
50% gray reveals faint clouding or backlight bleed that black and white can mask.
The grayscale gradient exposes color banding and backlight-uniformity faults that a flat fill can't show.

Everything runs locally, entirely inside your browser. Nothing about your screen, your device, or what you see is ever uploaded, transmitted, or stored anywhere.

Dead Pixel vs. Stuck Pixel vs. Hot Pixel

These terms get used interchangeably, but they describe different faults with different fix odds.

Dead pixel: a subpixel receiving no power at all. It stays black regardless of the surrounding color, so it's most visible on white and invisible on black. Essentially unrecoverable.
Stuck pixel: a subpixel receiving power but locked onto one channel, always fully red, green, or blue. Visible against any background. Sometimes fixable, since the transistor still works.
Hot pixel: a stuck pixel locked fully on and bright, most obvious against black. Often used interchangeably with "stuck," but the black-versus-white behavior is the real distinction.

How to Run the Test Properly

A test only tells the truth under the right conditions; sloppy setup is the top reason people mistake dust for a dead pixel or miss a real one.

Clean the screen with a dry microfiber cloth first; smudges mimic dead and stuck pixels under white.
Dim the room so glare doesn't hide faint faults.
Use true fullscreen, not a maximized window; visible browser chrome hides part of the panel.
Set native resolution and disable scaling; a scaled image can blend a bad pixel into its neighbors.
Check the whole panel methodically, including corners and edges.
Test at a couple of brightness levels, since some stuck pixels show more at higher brightness.

Per-Device Instructions

The test works in any browser, but reaching a true fullscreen, unscaled view differs slightly by device.

Windows Laptop or Desktop

Click start and let fullscreen take over (press F11 if needed). In Display settings, confirm scaling is 100% and resolution matches the recommended native value.

MacBook

Use the green fullscreen button, or Control+Command+F, in Safari or Chrome. Keep System Settings > Displays on "Default" rather than a manually scaled resolution.

Android Phone

Open in Chrome, tap to start, and allow the fullscreen prompt to hide the status and navigation bars. Raise brightness and disable adaptive brightness first.

iPhone

Open in Safari and tap to start; Safari hides the address bar, though a thin strip may remain since iOS lacks fully immersive fullscreen, so check those edges by eye. Wipe the screen first: fingerprint oil is a common false positive.

External Monitor

Connect via wired HDMI or DisplayPort rather than wireless casting, and turn off the monitor's sharpness, overscan, or aspect-ratio processing.

TV

Connect a laptop or phone at native resolution over HDMI rather than screen mirroring, and disable overscan and picture-enhancement processing in the TV's settings.

Fixing a Stuck Pixel: The Fixer Tool and the Massage Method

Dead pixels can't be repaired: no power reaches the subpixel. Stuck and hot pixels are different, since the transistor still functions, rapid flashing or gentle pressure sometimes coaxes it back. Treat any fix as a coin-flip bonus, not a guarantee.

The stuck-pixel fixer flashes rapid, randomized RGB noise across the screen to try to un-stick a subpixel. This kind of flashing can trigger seizures in people with photosensitive epilepsy. It is strictly opt-in and never runs automatically; avoid it if you or anyone nearby has a seizure history, and stop immediately if you feel discomfort or dizziness.

Turn the screen off or show a solid black fill.
Wrap a soft cloth around your fingertip — never anything hard or sharp.
Apply very gentle, even pressure on the spot for a few seconds, then release.
Turn the screen back on and re-run the test.
Repeat once or twice at most; excess pressure risks damaging healthy pixels nearby.

When Is It a Warranty Case?

Warranty coverage isn't arbitrary. Most reputable brands reference ISO 9241-307, which sorts panels into pixel-fault classes defining how many dead, stuck, or hot subpixels are acceptable before a panel counts as defective; Class 1 allows zero, Class 2 permits a small number.

Check your manufacturer's specific policy; some publish stricter "zero bright subpixel" guarantees beyond the ISO baseline.
Dead and bright/stuck subpixels are sometimes counted differently within the same policy.
Document the fault: which color it appeared on, its position, and the total count.
Check your purchase date against the warranty window; pixel claims are often honored only briefly.
Contact the retailer or manufacturer with your findings; approval usually depends on matching their published policy.

Buying Used or Refurbished Electronics? Checklist

A pixel fault is easy for a seller to hide and easy for a buyer to miss at a glance. Running this test first takes two minutes and can save an expensive mistake.

Ask to test the device in person, or request video of the seller running this test.
Step through all nine fills, not just white; some faults only show on black or a saturated color.
Watch the gradient for banding or patchy brightness, a sign of a tired backlight.
Check corners and edges closely, where wear is most common on used panels.
Confirm the return policy explicitly covers display defects.
Use the ISO 9241-307 class information to judge whether a found fault is worth walking away over.

Frequently asked questions

Can dead pixels fix themselves?

Essentially never. A dead subpixel gets no power and no signal will correct that; it's a hardware failure, not a glitch. If a spot disappears on its own, it was likely dust or a stuck pixel that resolved.

Does pressing on a dead pixel actually work?

No. Pressure can only help stuck or hot pixels, where the subpixel is powered but locked on the wrong signal; a dead one has no power to jostle. Run the color test first: invisible on black but visible on white points to dead, while a fixed color on multiple fills points to stuck.

Is a dead pixel covered under warranty?

It depends on your manufacturer's pixel-fault policy and fault count. Most reference ISO 9241-307's fault classes, and many now guarantee zero bright subpixels even where a dead one or two is tolerated. Check your product's policy, document the fault, and contact support within the warranty window.

What causes dead pixels in the first place?

Most result from manufacturing imperfections, a transistor that didn't form correctly or a subpixel wired wrong. Physical impact, pressure, or age can also cause one to fail later. It's rarely anything you did, and normal software use doesn't cause it.

How do I tell a dead pixel from dust under a screen protector?

Dust looks similar at a glance, but two tells separate them. A dead pixel stays in exactly the same spot no matter how you tilt or clean the screen, while dust can shift slightly. Run the color test: a dead pixel behaves consistently across every fill, while dust often catches light differently depending on angle.

Is a stuck pixel the same thing as a dead pixel?

No. A dead pixel has no power and always looks black; a stuck pixel is powered but locked onto one color signal, appearing as a fixed dot regardless of content. Stuck pixels are sometimes fixable with flashing or pressure; dead pixels essentially are not.

How many dead pixels are considered normal on a new screen?

ISO 9241-307's fault classes permit a small number of dead or stuck subpixels on new panels depending on resolution and class, so one fault isn't automatically a defect. Many manufacturers now advertise a stricter zero-bright-subpixel guarantee, so check your specific model's stated policy.

Will a dead pixel spread or get worse over time?

No. A dead pixel is a fixed failure and won't spread or worsen physically. Additional, unrelated pixels can fail elsewhere as a panel ages, which can feel like spreading but is a separate fault; several new faults appearing quickly is worth flagging to the manufacturer.

Can running a dead pixel test damage my screen, and is the stuck pixel fixer safe?

The color test itself is completely safe: it just shows static solid colors like any normal image. The optional fixer is different: it flashes rapid RGB noise, carrying a real seizure risk for photosensitive epilepsy, so it's strictly opt-in, never automatic, and best avoided if that risk applies to you or anyone nearby.

Does display scaling or resolution affect how accurate the test is?

Yes. A non-native resolution or active scaling means the operating system resizes or blends the image before it reaches the panel, which can shift or blur a bad pixel into its neighbors. Set native resolution and disable scaling before testing for the most accurate result.

Every part of this test runs locally in your browser; nothing about your screen, your device, or what you find is ever uploaded, transmitted, or stored anywhere.