Screen Test
Check your monitor, laptop, phone or TV with a free online screen test. Solid full-screen colors make dead pixels, dust and uneven areas easy to see.
Clean the screen first, then start the test and look at each color in turn.
What Is a Screen Test?
A screen test fills your display with plain colors and simple patterns, one at a time, so you can look at the panel itself instead of the picture on it.
In normal use your screen is busy. Text, photos and video move around and hide small faults. A missing pixel or a dim patch can sit there for months before you notice it.
When the whole screen shows one flat color, there is nothing to hide behind. A pixel that stays black, a dot stuck on red, a bright edge or a dusty mark all stand out right away.
That is the whole idea. No software, no settings to change, and nothing to learn first. You look at each color and check whether the screen shows it evenly from corner to corner.
What This Screen Test Checks
One pass through the colors tells you about most of the faults you can see with your own eyes.
Dead and Stuck Pixels
Small dots that stay black, or stay on one color, while the rest of the screen changes. These are the most common faults on a new panel.
Screen Colors
Whether red looks like red across the whole panel, and whether one side of the screen looks warmer or cooler than the other.
Brightness and Contrast
The white screen shows how bright the panel gets. The black screen shows how dark it can go, which is where cheap panels usually give up.
Backlight Bleed
Light leaking in from the edges, easiest to see on a black screen in a dark room. Most panels have a little. A lot is worth a return.
Dust, Marks and Scratches
Plain white and plain gray show every mark on the glass, including dust that has worked its way under the surface.
Uneven Areas
Patches that look darker or cloudy compared to the rest of the panel. A solid gray screen shows this best.
How to Run the Screen Test
The whole check takes about five minutes. Do it in a room that is not too bright, and give each color a few seconds before you move on.
Clean the Screen First
Wipe the screen with a soft dry cloth. Dust and finger marks look a lot like screen faults, and cleaning first saves you a lot of worry.
Start the Test
Press Start Screen Test. The page goes full-screen and shows one solid color, with the site and the browser out of the way.
Look at Each Color
White comes first, then black, red, green and blue. Click, tap or press the right arrow key for the next color. The left arrow takes you back.
Nothing changes on its own, so you can stay on one color as long as you like.
Check the Whole Panel
Start in the middle, then work out to the corners and along the edges. Sit about an arm away, close enough to see a single dot but far enough to see the whole screen.
Note Anything That Stays
You are looking for anything that does not change with the background: a dot, a line, a bright edge or a cloudy patch. Note where it is on the screen.
Go Back and Check Again
Return to the same spot on two or three colors. If the mark moves or disappears, it was dust. If it stays in exactly the same place, it is on the panel.
Press Escape when you are done, and the page comes back as it was.
What Each Color Shows You
Each color in the test has a job. Knowing what to look for on each one makes the check much faster.
White lights up every part of every pixel. Dark dots, dust and marks on the glass show up clearly, and you can see whether one corner looks dimmer than the rest.
Black turns everything off. Now the only things you can see are bright dots that should not be lit, and light leaking in from the edges of the panel. A dark room helps here more than anywhere else.
Red, green and blue each light up one part of the pixel on its own. A pixel that has lost its red part looks wrong on the red screen and normal on the other two, which tells you a bit more about the fault.
These same colors are what a screen color test uses, and you can open any of them on their own from the color pages if you want longer with one of them.
Screen Test for PC, Laptop, Phone and TV
The test runs online in your browser, so it works on anything with a screen and an internet connection. Only the way you look at the screen changes.
PC and Monitor
For a PC screen test, open this page on the computer the monitor is plugged into and go full-screen. If you run two or three monitors, drag the browser window onto each one and test them separately.
Check the cable too. A loose or damaged cable can cause flicker and odd colors that look like a panel fault.
Laptop Screen Test
A laptop screen test works the same way. Set the brightness to a level you can look at comfortably, and close the lid halfway once to see if the picture flickers.
Laptop panels also get pressure marks from the keyboard. A plain white screen shows those as faint light patches.
Phone and iPhone
On a phone, hold the screen steady and move your eyes across it instead of moving the phone. An iPhone screen test needs nothing extra: the browser is enough.
Turn off auto brightness first, or the screen will change level while you are looking at it.
Tablet
A tablet gives you a bigger panel to look over, so take a little longer and pay attention to the corners, where faults are easiest to miss.
TV
Many smart TVs have a browser you can open this page in. If yours does not, show a plain white and a plain black image on the TV and check it the same way.
Step back to your normal seat once you are done, because some faults only matter at the distance you actually watch from.
Screen Color Test
A screen color test is the same idea with the colors on their own. Instead of running through a set order, you open one color and stay with it.
This is useful when you already know roughly where the problem is. If you saw a bright dot during the main test, open a black screen and look at that spot properly. If you saw a dark dot, use a white screen.
It also helps when you compare two screens. Put the same solid color on both and any difference in warmth or brightness is easy to see side by side.
Screen Color Test
Step through the solid colors one at a time.
White Screen
For dark dots, dust and marks on the glass.
Black Screen
For bright dots and light leaking in at the edges.
Red Screen
Checks the red part of every pixel on its own.
Green Screen
Green is the color your eyes pick faults out of most easily.
Blue Screen
Useful for dark blue banding and uneven areas.
Touch Screen Test
A color test checks what the screen shows you. It does not check whether the screen feels your finger, and those are two different parts of the same panel.
If taps land in the wrong place, or one area of the screen ignores you, that is the touch layer and not the pixels. A touch screen test is the check for that: you drag a finger across the whole screen and watch for any part that does not follow.
It is worth doing on a used phone or tablet before you pay, and after a drop. A screen can look perfect and still have a dead patch of touch in one corner.
Common Screen Problems
These are the faults a screen test usually turns up, and where to look at each one more closely.
Dead Pixels
A pixel that stopped working. It stays black on every color and is easiest to see on a white screen.
Stuck Pixels
A pixel stuck on red, green or blue. It stays lit when the screen goes black, which is where you should look for it.
Backlight Bleed
Light leaking in around the edges of a black screen. Common on LCD panels, and a matter of how much rather than whether.
Burn-in
A faint shape left behind by an image that sat in one place for a very long time. Solid gray and white screens show it best.
Ghosting
A trail behind moving objects. You need moving content to see this one, so a solid color will not show it.
Flicker
A screen that pulses instead of holding steady. It often shows up as tired eyes before you notice it with your eyes alone.
When to Run a Screen Test
A few minutes at the right moment can save you a lot of trouble later.
On a New Screen
Test in the first few days, while returning it is still simple. Check the warranty at the same time, because every brand sets its own rule for how many faulty pixels it will replace a screen for.
Before Buying Second Hand
Ask the seller for two minutes with the screen. A white screen and a black screen tell you more than any photo in a listing.
After a Drop or a Knock
Look for lines, cloudy patches or a dead area of touch. These show up straight away, even when the glass looks fine.
When Something Looks Off
If the screen feels dimmer on one side, or a dot keeps catching your eye, a full-screen color will tell you whether it is real or your eyes playing tricks.
Before You Sell
Run the test so you know exactly what to tell the buyer. It is easier to sell a screen with one known fault than one with a surprise.
Other Tests You Can Run
The screen test covers the basics. These go further into one part of the display.
Dead Pixel Test
The full check for dead, stuck and bright pixels, with the same colors.
Monitor Test
Built around external monitors and multi-screen setups.
Display Test
A quick look at any display for problems you can see.
Stuck Pixel Test
For a pixel stuck on one color, with a fixer that sometimes frees it.
Refresh Rate Test
Shows how many frames your screen draws each second.
Contrast Test
Checks how well your screen separates light and dark tones.
Frequently Asked Questions
What does a screen test check?
It fills your screen with solid colors so you can look for dead and stuck pixels, dust, uneven brightness, backlight bleed and colors that look wrong.
Do I need a code to run the screen test?
No. There is no code to enter and no app to install. Open the page, press the button, and the test runs in your browser.
Is this screen test free?
Yes. Every test on this site is free and you do not need an account.
How long does a screen test take?
About five minutes for a careful look at every color. You control the pace, so you can stay on one color as long as you want.
Can I test my laptop screen?
Yes. Open this page on the laptop and start the test. Set the brightness to a comfortable level first so the colors look even.
Can I test my phone or iPhone screen?
Yes. The test runs in the browser on an iPhone, an Android phone or a tablet. Turn off auto brightness first so the screen does not change while you look at it.
Does this test the touch screen?
No. This test checks what the screen shows. To check whether the screen responds to your finger, use the touch screen test.
What is the best color for finding faults?
White for dark dots and dust, black for bright dots and light leaking at the edges. Most faults show clearly on one of those two.
My screen looks fine. Do I still need a test?
A quick check is worth it on a new screen or one you are about to buy. Small faults are easy to miss in normal use and hard to argue about later.
Ready to Test Your Screen?
Wipe the screen, then start the test and look at each color in turn.
It is free, it runs online in your browser, and Escape brings you back at any time.
Start Screen Test