Monitor Test
Fill any monitor, laptop, phone or TV screen with solid colors to check it for visible faults.
Display and monitor tests
Find dead pixels, check the refresh rate, and look for backlight bleed, uneven brightness, color problems, banding and ghosting.
All display tests
Dead Pixel Test
Fill the screen with five solid colors to spot dead, stuck and hot pixels.
Stuck Pixel Fixer
Flash random colors over the whole screen for a timed run to try to free a stuck pixel.
Refresh Rate Test
Check the refresh rate your screen is running at, in Hz, and see how smooth that rate looks.
Ghosting Test
Watch moving blocks, bars, text and lines for ghosting trails, motion blur and overdrive halos.
Screen Uniformity Test
Fill the screen with white, 50% gray, black, red, green and blue to spot clouding, mura and tint shifts.
Backlight Bleed Test
Show full-screen black and dark grays to spot backlight bleed and IPS glow on an LCD.
Brightness Test
Step through labeled gray levels from black to white to set your screen brightness by eye.
Contrast Test
Check black level, black crush and white clipping with numbered gray steps from 0 to 255.
Gamma Test
Estimate your screen’s gamma with a striped chart, then check midtones, shadows and highlights.
Gradient Test
Show smooth full-screen gradients to reveal color banding and posterization on any screen.
Screen Color Test
Fill the screen with pure red, green, blue, gray or any hex color to check for tint and patches.
HDR Test
See what your browser reports about HDR and wide color, and compare HDR and P3 test patches.
Screen Burn-In Test
Fill the screen with flat gray, white, black and color fields to spot image retention and burn-in.
Screen Flicker Test
Gray and white fields for the pencil and camera flicker checks, plus optional flashing patterns.
Screen Geometry Test
Grid, circle and overscan patterns to check a screen for stretching, centering and cropped edges.
Screen Cleaner
A black or white full-screen field shows dust and smudges, and taps are ignored until you unlock.
Blooming Test
Move bright shapes, dots and text over black to see halos from local dimming on an LCD.
Text Clarity Test
Check text sharpness: colored text, 1-pixel lines and dots show chroma subsampling and blur.
How to test a monitor
A display test fills your screen with a controlled pattern, such as a solid color, a gradient or a moving shape, so faults become easy to see. Your eyes do the checking. On a new or second-hand monitor, laptop, phone or TV, go through these in order, ideally before the return window closes:
- The Monitor Test: solid colors across the whole panel, for tint, blotches and obvious faults.
- The Dead Pixel Test: a dot that stays black, white or one color while the rest of the screen changes.
- The Backlight Bleed Test and the Screen Uniformity Test: glow along the edges and uneven patches on dark and gray screens.
- The Gradient Test and the Gamma Test: banding in smooth gradients and lost shadow detail.
- The Refresh Rate Test and the Ghosting Test: the refresh rate the screen is running at, and how clean motion looks.
Which test do I need?
| If you notice | Try |
|---|---|
| A dot that stays black, white or one color | Dead Pixel Test, Stuck Pixel Fixer |
| Bright patches or glow along the edges of a dark screen | Backlight Bleed Test, Screen Uniformity Test |
| Halos around bright objects on a dark screen | Blooming Test, Backlight Bleed Test |
| Uneven brightness, blotches or a tinted area | Screen Uniformity Test, Monitor Test, Screen Color Test |
| A high-refresh monitor that does not feel smooth | Refresh Rate Test, Ghosting Test |
| Trails, blur or halos behind moving objects | Ghosting Test |
| Stripes or steps in smooth gradients | Gradient Test, Gamma Test |
| Dark scenes look crushed, or bright ones washed out | Brightness Test, Contrast Test, Gamma Test |
| A faint image that stays on the screen | Screen Burn-In Test |
| Visible flicker, especially at low brightness | Screen Flicker Test |
| A stretched, cropped or distorted picture | Screen Geometry Test |
| HDR does not seem to work | HDR Test |
| Dust and smudges are hard to see while cleaning | Screen Cleaner, Dead Pixel Test |
| Colored text looks blurry or fringed | Text Clarity Test, Screen Resolution Test |
Before you start
- Clean the screen with a soft, dry cloth first so dust is not mistaken for a faulty pixel; the Screen Cleaner shows dust on black and smudges on white.
- Use the brightness you normally use, and dim the room for the black and dark gray patterns.
- Look at the whole panel for each pattern, including the corners and edges.
- On an OLED screen, do not leave a static pattern on screen for hours; step through the tests instead.
Frequently asked questions
How do I test my monitor?
Clean the screen, dim the room and run the Monitor Test to look at solid colors across the whole panel. Then check for faulty pixels with the Dead Pixel Test, look for bleed on a black screen with the Backlight Bleed Test, and confirm the refresh rate. The whole check takes about ten minutes; the new monitor guide walks through it.
Can these tests damage my screen?
No. They only show ordinary images, like any web page. The Stuck Pixel Fixer flashes rapidly, so avoid it if you are sensitive to flashing light, and avoid leaving any static image on an OLED screen for hours.
Do display tests work on phones and TVs?
Yes. Any device with a modern browser can run them. On a phone, tap Start to go fullscreen; on a smart TV, open the page in the TV browser. Some TV browsers do not support fullscreen, or report a lower refresh rate than the panel can show.
Can a browser measure color accuracy or response time?
No. Color accuracy needs a hardware colorimeter, and response time and input lag need a photodiode or a high-speed camera. These tests show patterns that make problems visible to you; they are not measurements.
Guides
- How to test a new monitorTest a new monitor on day one, while it can still go back: set the native resolution, then check dead pixels, backlight bleed, uniformity, banding, gamma, refresh rate and ghosting in your browser. The whole check takes about 10 minutes.
- Dead pixel vs stuck pixel vs hot pixel: what is the difference?A dead pixel stays black on every color, and no software can repair it. A stuck pixel stays lit in one color and a hot pixel stays white, both easiest to see on black; either can sometimes recover.
- Dead pixel policy: how many faulty pixels each brand allowsMost monitor makers replace a screen only when faulty pixels pass a set limit, and they count bright faults more strictly than dark ones. Dell’s Premium Panel Exchange models and some premium lines from Lenovo, ASUS and Gigabyte are replaced for a single bright pixel; others accept a few. Count yours, then compare.
- How to calibrate a monitor without a colorimeterWithout a colorimeter you can set four things by eye: brightness, so the darkest gray steps just separate from black; contrast, so the brightest stay distinct from white; gamma, to about 2.2; and white balance, until gray shows no tint. Color accuracy needs a colorimeter.
- Why is my monitor flickering? How to find the cause and fix itScreen flicker usually comes from the display driver, an app, the cable or refresh rate, variable refresh in games, or PWM dimming at low brightness. On Windows, check Task Manager first: if it flickers along with everything else, fix the display driver; if it stays steady, an app is the likely cause.
- IPS vs VA vs OLED: how monitor panel types differIPS keeps colors steady from wide angles but shows weaker blacks; VA has the most contrast of any LCD type; OLED lights each pixel itself, so black is truly black, but static images can cause burn-in. TN, the oldest type, is fast and affordable, with the narrowest viewing angles.
- How to test a used laptop before you buy itCheck the case and hinges, then run the screen, keyboard, touchpad, speaker, microphone and webcam tests in the laptop’s own browser and try every port and the charger. Battery health and the serial number come from the operating system; allow about 15 minutes.