Guide
How to Test a New Monitor
A new monitor should be checked while you can still return it. The useful checks are specific: bad pixels, light leaking in the corners, and gray that is not even. A browser can show the fields for those. It cannot certify the panel.
What to check before you keep it
Pixels first
A dead pixel stays dark. A stuck pixel stays bright. Dust moves. The dead pixel test is the tool for that, not a screenshot of a desktop.
Dark scenes second
Backlight bleed and IPS glow are easy to mix up. The bleed test is black and dark gray, in a dim room, from straight in front.
Gray third
50% gray shows clouding. Darker grays show corners. The uniformity test is those steps. It does not measure nits.
The one sitting
The monitor test walks pixels, five grays, a ramp, a grid, and a moving bar. Use it when you want one pass, then open the longer test if a step looks wrong.
Why this is not another color page
A new monitor should be checked while you can still return it. The useful checks are specific: bad pixels, light leaking in the corners, and gray that is not even. A browser can show the fields. It cannot certify the panel.
The solid black, white, red, green, and blue screens are still the right tools when you want one color. They are the wrong place to stop if you have not changed fields, sat straight on, or dimmed the room. This guide is the order, and the test pages are the fields.
Buyers also ask about refresh rate, blur, and OLED image retention. Those are real questions. They are not answered by a flat color, and this site does not invent a millisecond or a hertz reading from the browser.
How to test a new monitor
- Note the return date. Give the panel a few minutes on power. Set the resolution the monitor expects. Clean the outside of the glass once.
- Check pixels. Open the dead pixel test. Step through every solid color, not only red, green, and blue. Pause on a dot. Wipe only if you think it is dust.
- Check the corners. Dim the room and open the backlight bleed test. From straight on, a patch that stays put is bleed. A sheen that shifts is IPS glow. OLED panels do not have backlight bleed.
- Check gray. Open the uniformity test. Hold 50% gray, then the darker steps, then 75%. Look from the center. The page does not report nits.
- Use the short pass if you are in a hurry. The monitor test runs the colors, five grays, a ramp, a grid, and a moving bar. It is not a score. If one step looks wrong, go to the matching test.
- Leave the browser for the rest. Confirm the refresh rate in the system display settings. Wiggle the cable. On an OLED, a leftover logo on a gray field can be temporary retention or permanent burn-in, and a web page cannot tell those apart.
Why check a new monitor this way
The return window is the deadline
A pixel, a corner leak, and a blotchy gray are easiest to act on while the seller still has to take the screen back. This guide is the order. The tools are the fields. Neither one is a warranty department.
Look at the panel, not at a score
Each tool shows a color and tells you what that color is for. None of them invent a pass, a grade, or a percentage. If a page offered a score without measuring the panel, the score would be fiction.
Separate the jobs
A stuck pixel, IPS glow, and a dirty gray are different things that show on different fields. Doing them in one unnamed slideshow makes it easy to misname what you saw. The links below keep the jobs apart.
Leave the lab claims out
Hertz, nits, and milliseconds belong to the monitor’s spec sheet and to the operating system, not to a color in a browser. This guide says where those checks live, and it does not fake the numbers.
A practical order for a new screen
Before you start
Give the panel a few minutes on power. Set the computer to the resolution the monitor expects. Wipe the glass once so a fingerprint is not a pixel. Note the return date. Sit where you will sit.
Pixels, then black, then gray
Open the dead pixel test and walk white, black, red, green, blue, and gray. Dim the room and open the backlight bleed test. Then hold the grays on the uniformity test. The monitor test is the short version of that order.
Outside the browser
On the computer, the display settings show the refresh rate in use. Watch a game or a scrolling page you already have if you care about blur. Wiggle the cable and try the port you will keep. Those failures are not in a color field.
When to stop and talk to the seller
A cluster of dead pixels, a bright stuck pixel in the center, or a corner leak you can see from your chair is worth checking against the written policy before the window closes. A faint edge speck, or glow that only appears when you lean, is something many people keep. The pages show the field. You decide.
When to stop and talk to the seller
Return rules belong to the seller. A cluster of dead pixels, a bright stuck pixel in the center, or a corner leak you can see from your chair is worth checking against those rules before the window closes. A single faint speck at the edge, or glow that only appears when you lean over, is something many people keep.
Do not use a browser frame counter as proof the monitor is or is not 144 Hz. Do not treat a gray field as proof of permanent OLED burn-in. Do not expect this site to email you a certificate.
Start with the monitor test if you want one sitting, or go straight to pixels, bleed, and uniformity.
Frequently asked questions
What should I test on a new monitor first?
Pixels, then corner light in a dim room, then gray uniformity. Those are the faults people can see and still return. Refresh rate and cables come after, outside this page.
How do I test a used monitor?
Use the same three checks, and add a look for a leftover static image on gray if it is an OLED. Ask the seller to let you try the ports you will actually use. A color field will not show a bad HDMI port.
Is a black screen enough?
No. Black helps with stuck pixels and bleed. Dead pixels show on white. Subpixels show on red, green, and blue. Clouding shows on gray. One color is one check.
Can I do this in the shop?
Yes, if you can open a browser. Full screen, then the same fields. Shop lighting hides bleed. If you can, look again at home in a darker room before the return window ends.
How do I check 144 Hz?
In the operating system’s display settings, not on this site. A web page that counts frames is not the number the graphics card is sending.
How do I test an OLED for burn-in?
Look at gray and at other flat colors for a ghost of a taskbar or a logo. A faint image that fades may be temporary retention. A web page cannot declare the panel permanently burned in.
The full screen test had a toolbar at the bottom.
The test pages do not put a toolbar on the color. Full screen is the field. Click for the next one. Esc leaves.
Which page is the one I should bookmark?
The monitor test, if you want one pass. The three longer tests if you already know which fault you are looking for. This guide is the order, not the field.
How do I test a new monitor?
Clean the glass, set the native resolution, then run the dead pixel test, the backlight bleed test in a dim room, and the gray uniformity test. Use the monitor test if you only have a few minutes. Read the seller’s return rule before the window closes.
How long should I wait before judging uniformity?
A few minutes of power is enough to start the pixel check. For gray patches and corner light, let the panel warm while you do the pixel pass, then look again. There is no lab timer on this page. A cold panel can look patchier than it will later.
What can a browser not test?
It cannot read refresh rate, response time, peak brightness, or a permanent burn-in verdict. It cannot see a loose cable. Those checks are in the operating system, in real moving pictures, and in the cable you can reseat.
Do I need a downloaded program?
No. The four tools run in the browser. Full screen is only the field. There is no installer and no result file, because nothing was measured.
Is IPS glow a reason to return a monitor?
Glow that shifts when you move your head is common on IPS panels and is not the same as a leak that stays put. Many sellers do not treat ordinary glow as a defect. A bright corner that stays fixed from your chair is the one to compare with the policy.
What if I only have the phone I bought the monitor with?
A phone browser can show these pages on the phone’s own screen. To test the monitor, the page has to be on the monitor. Plug in a computer, or use the TV’s browser if that is the panel you are judging.
