Pixel Tests
Look for dead, stuck and bright pixels on your screen.
Dead Pixel Test
Use this free dead pixel test to check your screen for dead and stuck pixels. It runs in your browser on a monitor, laptop, phone or TV, and takes about five minutes.
Clean your screen and make sure the display is easy to see before starting the test.
Test Your Screen
This site gives you simple screen tests that run in your browser. The main one is the dead pixel test on this page. It fills the screen with one solid color at a time, so a faulty pixel has nowhere to hide.
The other tests come in four sets. Pixel tests look for dead, stuck and bright pixels. Screen tests check the display as a whole. Color tests show one color at a time. Advanced tests cover brightness, contrast and refresh rate.
Nothing needs to be installed, and five minutes is usually enough.
Screen Tests
Check your screen, monitor or display for problems you can see.
Color Tests
Show one full-screen color at a time, from white and black to red, green and blue.
Advanced Tests
Check brightness, contrast, refresh rate and other parts of your display.
What Is a Dead Pixel?
Your screen is made of many tiny dots called pixels. Each one can change color, and together they show the text, photos and video you see. A phone screen holds millions of them.
A dead pixel is a pixel that stopped working. It stays dark and does not change when the rest of the screen changes. On a white background it looks like a small black dot, in the same spot every time.
These dots are easy to miss in normal use. A busy photo hides them well, and many people think the mark is dirt and wipe the screen with no result.
A full-screen color solves that. When every pixel shows the same color, the one doing something else stands out at once.
Why Test Your Screen?
A screen can look fine in normal use and still have small faults. A few minutes of checking tells you whether that dot you keep seeing is dust or a pixel.
Dead Pixels
A dead pixel stays dark and never lights up. White and other light colors show these black dots best, which is why the test starts with white.
Stuck Pixels
A stuck pixel still lights up, but it is stuck on one color, often red, green or blue.
A black screen makes it easy to spot, and the stuck pixel test moves through several colors so you can be sure.
New Monitor
Check a new monitor or laptop in the first few days, while returning it is still simple.
Used Screen
Buying second hand? Ask for a few minutes with the screen before you pay. Plain white and plain black tell you more than any photo in the listing.
Display Problems
Solid colors also show dust under the glass, scratches, uneven brightness and light leaking in at the edges.
Dead Pixel Test vs Stuck Pixel Test
People often use the words dead pixel and stuck pixel for the same thing, but they are not the same.
A dead pixel gets no power, or its light is off. It stays black whatever the screen is showing, so a white background finds it fastest.
A stuck pixel is still working, but stuck on one color. It sits there as a small red, green or blue dot while everything around it changes, and a black screen shows it clearly.
A bad pixel test is the wider check. Bad pixel is a general word for any pixel that does not behave, so it covers dead, stuck and bright pixels in one pass.
A stuck pixel sometimes starts working again after a while. A dead pixel usually stays as it is. Neither is certain, so check a screen early.
How to Check for Dead Pixels
You do not need any software to check dead pixel problems. These steps take about five minutes and work on any screen with a browser.
Clean the Screen
Wipe the screen with a soft dry cloth first. Dust looks a lot like a dead pixel, and cleaning saves you a scare.
Start the Test
Press Start Dead Pixel Test. The screen goes full-screen with nothing else in the way, and a darker room helps.
The tool is a simple dead pixel detector: it does not scan the screen for you, but it makes faults easy for your eyes to find.
Look at Each Color
The test shows white, then black, red, green and blue. Give each color a few seconds. Click, tap or press the right arrow key for the next one.
Check the Full Screen
Look at the middle first, then the corners and edges. Faults near the edge are the ones people miss.
Look for Dots That Do Not Change
You want a dot that stays the same while the color behind it changes. A black dot on white, or a colored dot on black, is worth a closer look.
Check the Dot Again
Go back through the colors and look at the same spot. If the dot has gone, it was dust. If it stays black on every color, it is likely a dead pixel.
This second pass is what makes a dead pixel screen test worth trusting.
How to Fix a Dead Pixel
The honest answer first: a pixel that is properly dead usually cannot be fixed. It is getting no power, or its light has failed, and nothing you run in a browser brings back a light that has stopped working. Anyone promising a dead pixel fix that always works is selling something.
That is worth saying plainly, because the useful part comes next. Most of the dots people call dead pixels are not dead pixels at all, and three of the four things it could be are better news than the fourth.
So find out what you have before you give up on it. Clean the screen first, because dust is the most common answer of all. Then look at the same dot on white and on black. A dot that is black on white and invisible on black is dead. A dot that shows up on black is lit, which means it is stuck rather than dead, and a stuck pixel can sometimes be freed by running fast changing colour over it for ten minutes. That costs nothing and cannot damage anything, so it is worth trying on any dot that shows on black.
It is also worth knowing what does not work, so you do not waste an afternoon. Heat does not fix a dead pixel. Nor does cold. Nor does tapping the screen with a pen or anything else hard, which is a good way to turn one faulty pixel into several. The pixel fixing apps you can download are doing the same colour flashing described above, so they help with stuck pixels and do nothing for dead ones, whatever the app store page says.
Pressing on the panel is the one physical method with any history behind it, and it carries a real risk of cracking the screen or leaving a mark that does not fade. It is explained properly on the stuck pixel page, along with why it should be your last idea rather than your first.
If the dot really is dead and the screen is new, this is the point to stop trying things and start asking. Most manufacturers publish a policy on faulty pixels, and most of them need more than one before they will replace a panel. The number differs by maker, model and country, so look up your own. In the first few weeks after a purchase the shop is usually an easier conversation than the manufacturer.
And if it is staying, that is a fair outcome. One dead pixel does not spread to its neighbours, it does not damage anything else, and it does not get worse on its own. Most people stop seeing one within a week unless it sits in the middle of the screen.
One exception worth naming: a whole line or column that has gone wrong is not a dead pixel. That is the connection between the board and the panel, it will not respond to any of this, and it needs a repair.
Pixel Tests
These tests all look at pixels, but each one suits a different problem.
Dead Pixel Test
The test on this page, and what most people mean when they say pixel test. It runs through several full-screen colors and looks for pixels that stay dark.
It is the right place to start, because it finds all three faults in one sitting.
Stuck Pixel Test
For pixels stuck on one color. Red, green and blue screens make them stand out the most.
Bright Pixel Test
A bright pixel stays lit when it should be dark. A black screen turns these small white dots into the only thing you can see.
Bad Pixel Test
Not sure what you are looking for? A bad pixel test covers dead, stuck and bright pixels at once. Run the test above and note anything that does not change with the background.
Check Your Monitor, Laptop, and Other Screens
The test runs in a browser, so it works as a pixel tester on almost any screen.
Monitor
For a monitor pixel test, open this page on the computer the screen is plugged into. With two monitors, check each separately.
An LCD screen dead pixel usually looks like a small dark square with sharp edges.
Laptop
A dead pixel on a laptop screen is found the same way. Set the brightness to a level you can look at, then work through the colors.
Phone
Hold the phone steady and look across the whole screen. You can check dead pixel iPhone screens and Android phones the same way.
Tablet
A tablet gives you more screen to check, so take a little longer over the corners.
TV
Many smart TVs have a browser you can open this page in. If not, show a plain white and a plain black image instead.
How Does a Pixel Test Work?
Every screen is a grid of pixels, and each pixel is built from a red, a green and a blue part. Mixing those parts gives you every color you see.
When the screen shows one solid color, every pixel is asked to do the same job. Any pixel that does something else is easy to see, because it is the only thing different.
White turns all three parts on, so dark faults show against it. That is the heart of a black pixel test. Black turns everything off, so bright and stuck dots are the only light left.
Red, green and blue check one part of each pixel on its own. A pixel that has lost its red part looks wrong on red and normal on the other two.
That is all a broken pixel test is: one color at a time, with your own eyes doing the work. The same method helps with a burned pixel test, where you look for a faint shape left by an image that sat in one place too long.
When Should You Check Your Screen?
There is no need to test every week. These are the moments worth a few minutes.
After Buying a New Screen
Test in the first few days, while a return is still easy. Check the warranty too, because each brand sets its own limit for how many faulty pixels it will replace a screen for.
Before Buying a Used Screen
Ask the seller to show plain white and plain black. Two minutes now can save you from a screen you would look at every day.
When You Notice a Dot
If a small dot keeps catching your eye, find out what it is. Dust wipes away and a dead pixel does not.
On an Older Monitor
Faults appear over the years. A full-screen check shows uneven brightness or marks you have stopped noticing.
On a Laptop or Phone
Worth doing after a drop, and again before you sell the device.
Other Screen Tests
Once you have checked for dead pixels, these tests cover the rest of the display.
Screen Test
A general check of your display using full-screen colors and patterns.
Monitor Test
Made for an external monitor, useful when you run two screens side by side.
Display Test
A quick look at any display for problems you can see with your own eyes.
White Screen
A plain white screen. Good for dark dots, dust and marks on the glass.
Black Screen
A plain black screen. Good for bright dots and for light leaking in at the edges.
Frequently Asked Questions
What is a dead pixel?
A dead pixel is one tiny dot on your screen that has stopped working. It stays black and does not change when the picture changes.
How do I check for dead pixels?
Clean the screen, then press Start Dead Pixel Test. Look at each color and watch for a small dot that stays the same. Check the middle, the edges and the corners.
What is a stuck pixel?
A stuck pixel still lights up, but it is stuck on one color. It looks like a small red, green or blue dot that stays in place while the screen changes.
What is a bad pixel?
Bad pixel is a general word for any pixel that does not work as it should. It covers dead pixels, stuck pixels and bright pixels.
Can I test my laptop screen?
Yes. Open this page on the laptop and start the test. It is the same check you would run on any screen.
Can I test my monitor?
Yes. Open this page on the computer the monitor is plugged into. With two screens, test each one separately.
Can I check dead pixels on an iPhone?
Yes. The test runs in the browser, so it works on an iPhone, an Android phone or a tablet.
Is the dead pixel test free?
Yes. Every test on this site is free and you do not need an account.
Can a dead pixel be fixed?
A pixel that is properly dead usually cannot be, because its light has stopped working. Check what you have first: a dot that shows up on a black screen is lit, which makes it a stuck pixel, and those can sometimes be freed.
Do dead pixel fixer apps work?
They flash fast changing colour over the screen, which sometimes frees a stuck pixel and does nothing for a dead one. You do not need to install anything for that — the stuck pixel test page runs the same thing in your browser.
Does heat or pressure fix a dead pixel?
Heat and cold do nothing. Pressing on the panel occasionally helps a stuck pixel, but it can crack the screen or leave a lasting mark, so it belongs last rather than first. Never press on a phone or any OLED screen.
Does a dead pixel spread?
No. One dead pixel does not affect the ones around it and does not get worse on its own. A whole line or column going wrong is a different fault — that is the connection to the panel, not a pixel.
Ready to Check Your Screen?
Give the screen a wipe, then start the dead pixel test and see what is really there.
It is free, it runs in your browser, and you can leave at any time with the Escape key.
Start Dead Pixel Test