This free dead pixel test fills your entire screen with solid colors so you can spot dead, stuck, or hot pixels — plus a built-in flashing fixer for stuck ones. No download, no app.
RUNS ENTIRELY IN YOUR BROWSER · NOTHING IS RECORDED OR SENT ANYWHERE
Last updated: · Reviewed for accuracy against current browser APIs
Share:
Pick a color below or click "Start Test" to begin in fullscreen.
In fullscreen: ← / → or Space to change color · Esc to exit
A speck of dust or a smudge can look exactly like a dead pixel from a distance.
Click "Start Test."
The screen goes fullscreen and fills with a single solid color.
Look carefully across the entire screen.
Any dot that isn't the solid color — black, white, or colored — is a defective pixel.
Cycle through every color.
Some defects are far easier to spot on certain backgrounds, especially black and white.
Try the Stuck Pixel Fixer if you find one.
A stuck (not fully dead) pixel sometimes recovers after a few minutes of rapid color flashing.
Who tests for dead pixels, and why
Anyone unboxing a new monitor, laptop, TV, or phone runs this within the first day or two, since most retailers and manufacturers only accept an easy replacement within a limited return window — after that, a dead pixel becomes a lot more expensive to deal with. Buyers checking a second-hand screen use it before handing over payment, since a stuck or dead pixel is easy to miss in a quick glance but obvious once the whole screen fills with a solid color. Photographers and video editors test their monitors periodically since a stuck pixel in the wrong spot can quietly bias color-critical work without them noticing for weeks. If you're checking a monitor for color-critical work more broadly, it's also worth running our Screen Uniformity Test to catch vignetting or tinting that a single-color test alone wouldn't reveal. And anyone who's spotted a single odd-colored dot on their screen runs this to confirm whether it's a genuine hardware defect or just a bit of dust.
Dead, stuck, and hot pixels — what's the difference?
Type
What it looks like
Cause
Fixable?
Dead pixel
Always black, no matter what's on screen
No power reaching the pixel's transistor
Essentially never
Stuck pixel
Frozen on one color (usually red, green, or blue)
Transistor receiving power but stuck in one state
Sometimes, with pressure or flashing colors
Hot pixel
Always fully bright, often white
Transistor stuck fully "on"
Rarely
Sub-pixel defect
A faint tint rather than a solid dot
Only one of the red/green/blue sub-elements affected
Depends on the specific cause
Which color shows which defect best
Background color
Best for spotting
Black
Stuck and hot pixels (bright dots stand out clearly against black)
White
Dead pixels (a black dot is unmistakable against white)
Red / Green / Blue
Sub-pixel defects specific to that color channel
Gray
Subtle defects that a pure black or white background can hide
Since no single color reveals every type of defect equally well, cycling through all of them — not just checking one — is the only way to be reasonably confident a screen is genuinely clean.
How to try fixing a stuck pixel
A genuinely dead pixel can't be revived — there's no power reaching it, so nothing you do to the outside of the screen changes that. A stuck pixel is different, since its transistor is receiving power but frozen on one value, and that's occasionally reversible.
The gentle pressure method: turn the screen off, place a soft cloth over the stuck pixel's location, and press very gently for 5–10 seconds before turning the screen back on. Use minimal pressure — enough force to crack or scratch the panel will turn a minor annoyance into a real problem.
The flashing color method: this is what the Stuck Pixel Fixer above does — rapidly cycling red, green, blue, black, and white across the whole screen for an extended period, on the theory that repeatedly forcing the transistor to switch states can jolt it back to normal. Run it for several minutes; there's no universal guarantee, but it costs nothing to try and has no risk of harming the screen.
How many dead pixels are actually acceptable?
It might be surprising, but most screen manufacturers don't consider a single dead pixel a defect worth replacing under warranty. Many follow international guidelines like the ISO 13406-2 pixel-fault classes, which define how many dead, stuck, and always-bright pixels are tolerated before a screen qualifies as faulty — commonly allowing a handful of defects depending on the panel's class and resolution, not zero.
This is exactly why testing a new screen immediately matters: manufacturer policies vary, some are stricter than the ISO minimums and some aren't, and knowing your specific retailer or manufacturer's dead-pixel policy before your return window closes is the only way to know where you actually stand. Dell, LG, and Samsung all publish their own pixel-defect policy on their support sites if you search your specific model.
Why pixel defects happen in the first place
Every pixel on an LCD or OLED screen is built from microscopic transistors and sub-pixel elements manufactured in enormous, extremely precise batches. Even with modern fabrication techniques, producing a panel with millions of individually perfect pixels at scale is genuinely difficult — a single speck of dust, a microscopic manufacturing flaw, or a transistor that simply fails during the process can leave one pixel behaving differently from its neighbors. This is exactly why manufacturers build tolerance policies around a small number of defects rather than promising literal perfection on every unit that ships.
Pixel defects can also develop later, well after a screen leaves the factory. Physical stress from a drop or heavy pressure, prolonged extreme heat, certain manufacturing defects that only show up after months of use, and ordinary component aging can all cause a pixel to fail years into a screen's life, not just on day one. That's part of why it's worth running this test again occasionally, not only when a screen is brand new.
Frequently asked questions
How do I test my screen for dead pixels?
Click "Start Test," let the screen fill with a solid color, and look carefully across the whole display. Cycle through several colors with the arrow keys — any dot that never matches the background color is a defective pixel.
What's the difference between a dead pixel and a stuck pixel?
A dead pixel has no power reaching it and always looks black. A stuck pixel does receive power but is frozen on one color — usually red, green, or blue — instead of changing with the image. Stuck pixels can sometimes recover; dead pixels essentially never do.
Can a dead pixel be fixed?
Not reliably. A genuinely dead pixel has no power reaching its transistor, so there's nothing for software or gentle pressure to influence. A stuck pixel is a different story — that one is sometimes fixable.
How does the Stuck Pixel Fixer work?
It rapidly flashes red, green, blue, black, and white across the whole screen. Rapidly cycling colors can occasionally jolt a stuck transistor back into normal operation. It's not guaranteed, and it does nothing for a truly dead pixel, but it costs nothing to try.
What is a hot pixel?
A hot pixel is always fully bright rather than off or stuck on a single color — it looks like a permanently lit white or brightly colored dot regardless of what the screen is showing.
How many dead pixels are considered acceptable on a new screen?
This depends entirely on the manufacturer's own policy, and it's usually more than zero. Many display makers follow guidelines like the ISO 13406-2 classes, which permit a small number of pixel defects before a screen qualifies for replacement under warranty.
Should I test a new monitor or laptop right away?
Yes. Most retailers and manufacturers only offer an easy replacement within a limited return window, so running this test the day you get a new screen is genuinely worth the two minutes it takes.
Can this test damage my screen?
No. Displaying solid colors or flashing colors is completely normal use of a screen — it's no different from what any video or website already asks your display to do.
Does this work on a phone screen too?
Yes. The same solid-color and flashing approach works on phone and tablet screens, though dead and stuck pixels are somewhat less common on the smaller, newer panels typical in phones.
More tools on ProDeviceTest
Troubleshooting a whole screen rather than just pixel defects? These run the same way — instant, no download, right in your browser.
ProDeviceTest