Monitor Test
Check your monitor online with full-screen test colors and patterns. Look for dead pixels, uneven brightness, backlight bleed and color problems. No download needed.
Clean the monitor, set it to its native resolution, then start the test.
What Is a Monitor Test?
A monitor test puts plain colors and simple patterns on your monitor so you can check the panel itself. You are not looking at a photo or a game any more, just flat color from edge to edge.
That matters because a monitor hides its own faults. Moving pictures cover a dead pixel, and your eyes get used to a corner that is slightly darker than the rest.
With one solid color on screen there is nothing to hide behind. A black dot, a dot stuck on red, a bright edge or a cloudy patch all show up straight away.
This monitor test runs online in your browser. Open the page on the computer your monitor is connected to, press the button, and look at each color in turn.
What This Monitor Test Checks
One pass through the colors covers most of what you can judge with your own eyes.
Dead and Stuck Pixels
Dots that stay black, or stay on one color, while the screen changes. The most common fault on a new monitor, and the easiest to prove.
Monitor Colors
Whether red, green and blue look the same across the whole panel, and whether one side runs warmer than the other.
Brightness and Contrast
White shows how bright the monitor gets. Black shows how dark it goes, which is where cheaper panels give themselves away.
Backlight Bleed
Light leaking in around the edges of a black screen. Most LCD monitors have some. The question is how much, and whether you can see it in normal use.
Uneven Brightness
Patches that look darker or cloudier than the rest of the panel. A solid gray screen shows this better than white does.
Refresh Rate
How many frames your monitor draws each second, and whether it is really running at the Hz you paid for.
How to Run the Monitor Test
The check takes about five minutes. Work in a room that is not too bright, and give each color a few seconds before moving on.
Clean the Monitor
Wipe the panel with a soft dry cloth. Dust and finger marks look exactly like screen faults, and cleaning first saves you from chasing a speck of dirt.
Set It Up Properly
Set the monitor to its own native resolution and put brightness at the level you normally use. Testing a monitor at the wrong resolution makes everything look soft.
If the monitor has picture modes, use the standard one. Game and film modes change colors on purpose.
Start the Test
Press Start Monitor Test. The page goes full-screen and shows one solid color, with the browser and the site 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, and the left arrow to go back.
Nothing moves on its own, so you can stay on one color for as long as you want.
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 one dot, far enough to take in the whole screen.
Test Each Monitor Separately
With two or three monitors, drag the browser window onto each one and run the test again. A fault on the second monitor is easy to miss when you only test the main one.
Press Escape when you are done and the page comes back as it was.
Monitor Test Patterns and Images
People often look for a monitor test image to open in a photo viewer. A full-screen web page does the same job and does it better, because there is no scaling and no compression to muddy the result.
Each monitor test pattern has its own use. Solid colors find dead and stuck pixels. A gray screen shows uneven brightness. A gradient shows banding, where a smooth fade turns into visible steps. A grayscale strip shows whether dark tones stay separate instead of all turning to black.
Start with the solid colors, since they find the faults that matter most. Then move to the pattern that matches whatever looked wrong.
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.
Gray Screen
The best background for uneven brightness and cloudy patches.
Gradient Test
Shows banding in smooth color fades.
Grayscale Test
Steps from black to white so you can see where tones stop separating.
Monitor Test Online, No Download
You do not need monitor test software for any of this. There is nothing to download, nothing to install and no account to make.
Old monitor test tools were downloads because browsers could not go full-screen or show exact colors. Both of those problems went away years ago, so a web page can now do what a program used to do.
An online monitor test also has one clear advantage: it runs on the machine in front of you, including a work computer where you cannot install anything, and on a phone or a shop display where installing is not an option at all.
The only thing worth being careful about is the browser window itself. Always go full-screen before you judge anything, because a browser toolbar sitting over the panel hides the top edge, which is exactly where backlight bleed likes to show up.
Monitor Test Hz and Refresh Rate
Hz means how many times your monitor redraws the picture each second. A 60 Hz monitor draws 60 frames, a 144 Hz monitor draws 144, and higher numbers make movement look smoother.
A monitor sold as 144 Hz does not always run at 144 Hz. Windows and macOS often set a new monitor to 60 Hz until you change it yourself, and a cable that is too old or too cheap can hold the rate down as well.
This is worth checking on any monitor you bought for speed. It is also worth checking after a driver update, because display settings sometimes fall back to 60 Hz on their own.
Checking it takes a moment. Your display settings list the rate the screen is set to, and most monitors show the rate they are actually receiving somewhere in their own menu. If those two numbers disagree, the cable or the graphics setting is holding the monitor back rather than the monitor itself.
Monitor Test UFO and Motion
Solid colors cannot show you anything about movement, because nothing moves. For motion you need a moving object, and the best known test of that kind is the UFO test from Blur Busters, where small ships slide across the screen at a set speed.
A moving object shows two things a still color never will. Ghosting is a faint trail left behind the object, and it comes from pixels changing color too slowly. Skipping or stutter is movement that jumps instead of gliding, which usually means the frame rate and the refresh rate do not match.
Gamers care most about these, but anyone who scrolls a long document will notice bad ghosting once they know what it looks like.
Solid colours cannot answer any of this, so run the colour test first for pixels and panel faults and judge motion separately. Scrolling a page of text quickly is a rough but honest check: if the letters smear as they move, that is ghosting.
Mobile Display Test
The same test works as a mobile display test. Open this page on a phone or tablet, go full-screen and look at each color the way you would on a monitor.
Two things are different on a phone. Turn off auto brightness first, or the screen will change level while you are studying it. And hold the phone still, moving your eyes across the screen instead of moving the device, because a moving screen hides small dots.
Phone panels are usually OLED, which changes what you find. OLED goes properly black, so backlight bleed is not a thing, but burn-in is: a faint shape left behind by a keyboard or a status bar that sat in one place for months. A solid gray screen shows that better than black does.
Common Monitor Problems
These are the faults a monitor 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 shows up fastest on a white screen.
Stuck Pixels
A pixel stuck on red, green or blue. It stays lit when the screen goes black, so that is where to look.
Flicker
A monitor that pulses instead of holding steady. Often noticed as tired eyes at the end of a long day before it is seen.
Ghosting
A trail behind moving objects. Needs a moving test, so a solid color will never show it.
Banding
A smooth fade that arrives in visible steps instead of blending. Easiest to see on a dark gradient.
Burn-in
A faint shape left by an image that stayed in one place too long. More of an OLED problem than an LCD one.
When to Test a Monitor
A few minutes at the right time can save you a long argument later.
On a New Monitor
Test in the first few days, while sending it back is still simple. Check the warranty as well, because every brand sets its own rule for how many faulty pixels it will replace a monitor for.
Before Buying Used
Ask the seller for two minutes with the monitor showing plain white and plain black. That tells you more than any photo in the listing.
After Setting Up a New PC
Check the resolution and the refresh rate at the same time. A new build often runs a good monitor at 60 Hz until someone changes the setting.
When Something Looks Off
If one side looks dimmer, 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. A known fault is much easier to sell than a surprise one.
Other Tests You Can Run
The monitor test covers the basics. These go deeper into one part of it.
Dead Pixel Test
The full check for dead, stuck and bright pixels.
Screen Test
The same check written for any screen, not just an external monitor.
Display Test
A quick look at any display for problems you can see.
Refresh Rate Test
Measures the Hz your monitor is really running at.
Contrast Test
Checks how well the monitor separates light and dark tones.
Brightness Test
Compares brightness steps from dark to bright.
Frequently Asked Questions
Do I need to download monitor test software?
No. This monitor test runs online in your browser. There is nothing to download, nothing to install and no account to make.
What does the monitor test check?
Dead and stuck pixels, colors, brightness, contrast, backlight bleed and uneven areas of the panel. Refresh rate and motion have their own tests.
How do I check what Hz my monitor is running at?
Use the refresh rate test. It measures the frames your monitor draws each second, which is often lower than the number on the box until you change the setting yourself.
What is the UFO monitor test?
It is a motion test from Blur Busters where small ships move across the screen so you can see ghosting and stutter. Our ghosting and refresh rate tests cover the same ground.
Do I need a monitor test image?
No. A full-screen web page shows the colors and patterns directly, with no scaling or compression to get in the way of what you are looking at.
Which test pattern should I start with?
Solid colors. White finds dark dots and dust, black finds bright dots and edge light leaks. Move to gray and gradient patterns after that.
Can I use this as a mobile display test?
Yes. Open the page on a phone or tablet and run the same colors. Turn off auto brightness first so the screen stays at one level.
Can I test two monitors at once?
Test them one at a time. Drag the browser window onto each monitor and run the test again, because a fault on the second screen is easy to miss.
Is this monitor test free?
Yes. Every test on this site is free and you do not need an account.
Ready to Test Your Monitor?
Wipe the panel, go full-screen 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 Monitor Test