Free LCD / Monitor / Display Test
Inspect display colors, gradients, checkerboards and pixel uniformity with slow pattern cycling and an optional fullscreen view in your browser.
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How to use the lcd / monitor / display test
Inspect display colors, gradients, checkerboards and pixel uniformity with slow pattern cycling and an optional fullscreen view in your browser.
- Choose a solid color such as white, black, red, green or blue.
- Use Fullscreen display where supported and inspect the screen visually.
- Try gray, gradient and checkerboard patterns or choose a slow auto-cycle interval.
- Click the pattern to advance manually. Press Escape to leave fullscreen and stop cycling.
Who a display test helps
A screen test is useful whenever you need to judge a panel with your own eyes. People use it after buying a new or used monitor, before a return window closes, or when a laptop screen shows a tiny dot that might be a dead pixel or a speck of dust.
It also helps when you set up a second monitor and want to compare color and brightness side by side, or when a TV used as a computer screen looks uneven in dark scenes. Shops and IT staff can use the same patterns for a quick check before handing a device to someone.
The tool offers eight patterns: White, Black, Red, Green, Blue, Gray, a horizontal black-to-white Gradient and a Checkerboard of 32-pixel squares. You can step through them by hand or let them cycle every 2, 3, 5 or 10 seconds.
Worked example: checking a new monitor for pixel defects
Clean the screen with a soft cloth first, so dust is not mistaken for a defect. Open the page on the monitor you want to test, select White and then Fullscreen display.
On white, look for dark dots. A dot that stays black on every pattern is usually a dead pixel. Click the pattern to move to Black, and look for bright dots, which suggest a stuck or hot subpixel. Then step through Red, Green and Blue. A dot that glows red on the Blue pattern, for example, points to a subpixel stuck on red.
Next, choose Gray and the Gradient. A good panel shows a smooth ramp from black on the left to white on the right. Visible vertical bands suggest limited color depth or heavy processing. Finish with the Checkerboard to judge sharpness at the edges of the screen. Press Escape when you are done; leaving fullscreen also stops the cycle.
What each pattern reveals
Each pure color tests one channel. Red uses only the red subpixels, Green only the green and Blue only the blue, so a fault in one subpixel stands out clearly. White lights all three at full level, and Black turns them all off, which also exposes backlight bleed and glow at the corners on LCD panels.
The mid Gray pattern, at hex value 808080, is good for spotting uneven brightness, sometimes called clouding or a dirty screen effect. The Gradient shows banding, and the Checkerboard of sharp black and white squares helps you see blur, scaling or a softness that appears when the computer does not use the native resolution.
The tool only displays these images. It does not measure color, calibrate the screen or repair pixels, and patterns never change faster than once every two seconds.
Common mistakes to avoid
Do not judge the screen from a phone photo. Cameras add their own noise, moire and color shifts. Look directly at the panel instead, at a normal viewing distance and a comfortable brightness.
Avoid testing in a window that is not fullscreen when you are hunting for defects near the edges, because browser bars hide part of the panel. Also check that the display runs at its native resolution, since scaling can make a healthy checkerboard look blurry.
Remember that some faint glow on Black is normal for many LCD panels in a dark room. Compare with the manufacturer's pixel policy before deciding to return a screen.
Useful tips and limitations
- Inspect at a comfortable brightness and avoid judging a screen from a phone photograph.
- A visual test can help locate a suspect pixel, but cannot repair or certify the panel.
- Use the keyboard while the pattern area has focus: Enter or Space advances to the next pattern.
- Test a used monitor after it has been on for a few minutes, because some uniformity issues change as the panel warms up.
Common questions
Can the display checker fix dead pixels?
No. It displays patterns for visual inspection only and does not repair pixels.
Does the monitor test use rapid flashing?
No. Manual patterns and slow cycling at intervals of at least two seconds are used.
Which patterns are included in the display test?
White, Black, Red, Green, Blue, Gray, a black-to-white Gradient and a 32-pixel Checkerboard.
Does clicking a pattern stop the automatic cycle?
Yes. Clicking the pattern area or choosing a pattern button stops auto-cycling and shows the pattern you picked.
What if fullscreen does not work in my browser?
The tool shows a message and you can enlarge or maximize the browser window instead, then use the same patterns.
Device checks and recordings run locally without AI or media uploads. Permission is requested only when starting capture. Download anything you want to keep before leaving the page.