Display Test
Check any display online with full-screen test colors. Works on a mobile, laptop, tablet or monitor, with no app to install and no code to type.
Clean the display and turn off auto brightness, then start the test.
What Is a Display Test?
A display test fills the whole screen with plain colors so you can check the display itself instead of whatever you were looking at before.
Any display hides its own faults during normal use. Photos, apps and video move around and cover a dead dot, and your eyes quietly get used to a corner that is a little darker than the rest.
With one flat color on screen there is nowhere for a fault to hide. A dot that stays black, a dot stuck on red, a bright edge or a cloudy patch all become obvious.
This display test works online in your browser, so the same check runs on a phone, a tablet, a laptop or a monitor. Open the page on the device you want to check and start the test.
What This Display Test Checks
One run through the colors covers most of what you can judge by eye.
Dead and Stuck Pixels
Dots that stay black, or stay on one color, while the display changes. The most common fault on a new panel and the easiest one to prove.
Display Colors
Whether red, green and blue look right across the whole panel, and whether one side of the display runs warmer than the other.
Brightness
How bright the display goes, and whether the light is even from corner to corner or drops away at one edge.
Dust, Marks and Cracks
Plain white shows every mark on the glass, including dust under the surface and hairline cracks you cannot see when the display is busy.
Backlight Bleed
Light leaking in at the edges of a black screen. An LCD problem, so it shows on laptops and monitors more than on phones.
Burn-in
A faint shape left behind by something that sat in one place for months, like a status bar or a keyboard. Mostly an OLED problem.
How to Run the Display Test
The check takes about five minutes. Do it somewhere that is not too bright, and give each color a few seconds before you move on.
Clean the Display
Wipe the display with a soft dry cloth. Dust and finger marks look just like panel faults, and a phone screen picks up both by the hour.
Turn Off Auto Brightness
On a phone, tablet or laptop, switch auto brightness off first. If the display keeps changing level while you study it, you cannot tell a real dark patch from the sensor doing its job.
Start the Test
Press Start Display Test. The page goes full-screen and shows one solid color, with the browser out of the way.
Look at Each Color
White comes first, then black, red, green and blue. Tap, click or press the right arrow key for the next color, and the left arrow to go back.
Nothing changes on its own, so you can stay on one color as long as you need.
Check the Whole Panel
Start in the middle, then work out to the corners and along the edges. On a phone, hold the device still and move your eyes instead of moving the screen.
Check Anything You Find
Go back to the same spot on two or three colors. If the mark moves or disappears it was dust. If it sits in exactly the same place every time, it is on the display.
Press Escape when you are finished and the page comes back as it was.
Mobile Display Test
A phone screen is the display most of us look at all day, and the one most likely to be dropped. It is worth a check now and then, and always before you buy a used one.
Run the mobile display test online the same way as on any other device: clean the glass, turn off auto brightness, go full-screen and work through the colors. Hold the phone steady and move your eyes across the screen rather than waving the phone about.
On a used phone, look for three things in particular. A hairline crack shows as a thin line on white. A pressure mark from a tight case shows as a light patch. And a faint shape left by the status bar or the keyboard shows on gray, which is burn-in.
Do the check in a normal room rather than in bright sun, because a phone at full brightness outdoors hides almost everything.
Mobile Display Test Code
Many phones have a hidden test menu built in, and people often look for the mobile display test code that opens it. On a lot of Samsung phones you type *#0*# into the dialler and a menu of built-in tests appears, with red, green and blue screens among them.
These codes are not standard. Every brand picks its own, some phones need a different route through the settings, and on plenty of models the code does nothing at all. Newer Android versions have also closed off some of them.
You do not need any code for the test on this page. There is nothing to type, nothing to install and no menu to find. Open the page, press the button and the colors fill the screen.
The built-in menus are still handy for the parts a browser cannot reach, like the speaker, the vibration motor or the sensors. For the display itself, a full-screen color in a browser shows you exactly the same thing.
Display Test for Android
An Android display test runs in Chrome or any other browser on the phone. Nothing needs to be installed, which also means nothing needs permissions.
Most Android phones now use OLED panels, and that changes what you are looking for. OLED switches each pixel off on its own, so black is properly black and there is no backlight to leak at the edges.
What OLED does get is burn-in. If the same shape sits in the same place for months, it can leave a faint mark behind. Always-on displays, navigation buttons and the status bar are the usual suspects, and a solid gray screen shows the mark better than black or white.
One more Android habit worth turning off before you test: adaptive or extra-dim brightness modes. They shift the level while you are looking and make an even panel look uneven.
Laptop Display Test
A laptop display test online works the same way, with a couple of things that only laptops do.
Look for light patches in a grid pattern on a white screen. Those are pressure marks from the keyboard pressing against the panel while the lid is shut, and they are common on thin laptops carried in a tight bag.
Then open and close the lid slowly while a solid color is on screen. If the picture flickers, changes color or blinks out at a certain angle, the problem is usually the cable running through the hinge rather than the panel itself.
If your laptop is plugged into a monitor, test the two separately. Move the browser window onto each screen in turn, because a fault on the laptop panel is easy to miss when you spend all day looking at the external one.
Touch Screen Test
A color test checks what the display shows you. It says nothing about whether the screen feels your finger, and those are two separate layers of the same panel.
If taps land slightly off, or one strip of the screen ignores you completely, the touch layer is the problem and not the pixels. A touch screen test checks that: you drag a finger over the whole display and watch for any part that does not follow.
Run it on a used phone or tablet before you pay, and after any drop. A display can look perfect and still have a dead patch of touch in one corner, which is the kind of thing you only find out later.
Common Display Problems
These are the faults a display test usually finds, and where to look at each one more closely.
Dead Pixels
A pixel that stopped working. It stays black on every color and shows up fastest on a white screen.
Stuck Pixels
A pixel stuck on red, green or blue. It stays lit when the display goes black, so look for it there.
Screen Burn-in
A faint shape left by an image that stayed in one place too long. Common on older phones and on OLED televisions.
Uneven Brightness
Patches that look darker or cloudier than the rest. A solid gray screen shows this better than white does.
Flicker
A display that pulses instead of holding steady. Often felt as tired eyes before it is actually seen.
Touch Problems
Taps that land in the wrong place, or an area that ignores your finger. Nothing to do with the pixels.
When to Run a Display Test
A few minutes at the right moment saves a lot of trouble later.
On a New Phone or Laptop
Test in the first few days, while sending it back is still simple. Check the warranty too, because every brand sets its own rule for how many faulty pixels it will replace a display for.
Before Buying Used
Ask for two minutes with the device showing plain white and plain black. That tells you far more than the photos in any listing.
After a Drop
Look for thin lines, cloudy patches and dead spots of touch. These show up straight away, even when the glass looks fine.
After a Screen Repair
Run the test before you leave the shop. A replacement panel can arrive with its own faults, and it is much easier to raise that on the spot.
Before You Sell
Check the display so you know what to tell the buyer. A fault you mention is fine. A fault they find is a refund.
Other Tests You Can Run
The display test covers the basics. These look at one part in more detail.
Dead Pixel Test
The full check for dead, stuck and bright pixels.
Screen Test
The same check written for any screen you can open a browser on.
Monitor Test
Built around external monitors and multi-screen setups.
Touch Screen Test
Checks whether the display responds to your finger everywhere.
LCD Test
For LCD panels, where backlight and edge leaks matter most.
OLED Test
For OLED panels, where burn-in is the fault worth hunting.
Frequently Asked Questions
What does a display test check?
It fills the display with solid colors so you can look for dead and stuck pixels, dust, cracks, uneven brightness, burn-in and colors that look wrong.
Do I need a code for the mobile display test?
Not for this one. Some phones have a hidden test menu you open with a dialler code, but the test on this page needs no code and no app.
What is the display test code on Samsung phones?
On many Samsung phones you type *#0*# into the dialler to open a built-in test menu. Codes are different for every brand and some phones no longer accept them.
Can I run a display test on Android?
Yes. Open this page in Chrome or any browser on the phone and start the test. Turn off adaptive brightness first so the screen stays at one level.
Can I test my laptop display online?
Yes. Open the page on the laptop and go full-screen. Also open and close the lid slowly during a solid color, since flicker at an angle usually means the hinge cable.
Does this test the touch screen?
No. This test checks what the display shows. Use the touch screen test to check whether the screen responds to your finger everywhere.
Why does my phone display look uneven?
Often it is auto brightness changing the level while you look. Turn it off and test again. If a patch stays darker on gray, it is the panel.
What is the best color for finding display faults?
White for dark dots, dust and cracks. Black for bright dots and edge light leaks. Gray for burn-in and uneven areas.
Is this display test free?
Yes. Every test on this site is free and you do not need an account.
Ready to Test Your Display?
Clean the screen, turn off auto brightness 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 Display Test