Monitor Test: Check Your Screen With Test Patterns

A free online monitor and display test. Full-screen patterns for gradients and banding, black and white levels, gamma, sharpness, uniformity and color.

Ready: 14 patterns

How it works

Each pattern fills the screen, with what to look for in the hint.

Click, Space or the arrow keys for the next pattern, 1 to 9 to jump. Esc leaves.

Runs on your device. Nothing is uploaded or saved.

How to use the monitor test

Step 1Set up the screenUse the screen's native resolution and 100% browser zoom. Turn off night light, and dim the room a little.
Step 2Start the testTap Start test. Each pattern fills the screen with what to look for at the bottom. Tap or press an arrow key for the next one.
Step 3Record what you seeOn Black level, White level and Gamma, tap the patch the hint asks for. Leave with Esc to see and copy your result.

Monitor test result: black level visible from 2 percent and gamma about 2.2, with the 14 test patterns and the screen size — After the test: what you recorded on the level and gamma patterns, the patterns you checked and your screen's size.

How to test your monitor

Show test patterns full screen, one at a time, and compare what you see with what each pattern should look like. The patterns are drawn in your browser with exact values, one canvas pixel to one screen pixel, so what you see is what your screen does with them.

Before you start, set the screen to its native resolution and the browser zoom to 100%, and let the screen warm up for a few minutes. Sit where you normally sit. Work through the patterns in order, or jump with the Patterns menu or the number keys.

What each test pattern shows

Each pattern checks one thing. The hint bar on each says what to look for.

Monitor test patterns and what each one shows
Pattern	What it shows
White, black, red, green, blue	Dead or stuck pixels, tint, uneven patches
Gray and color gradients	Banding: steps in what should be a smooth fade
Gamma	Whether midtones are as bright as they should be
Black level	Shadow detail: brightness set too low or too high
White level	Highlight detail: contrast set too high
Sharpness	Blur, scaling and over sharpening on fine lines and text
Uniformity	Dark corners, tinted areas, clouding
Viewing angle	Color and contrast shift when you move your head
Color bars	Clean, distinct colors and an even gray scale

Calibrate brightness and contrast with the level patches

Set brightness with the black level pattern and contrast with the white level pattern. The black level pattern shows ten patches from 1% to 10% above black. Raise the screen's brightness until you can see the faint ones, then lower it until black still looks black around them.

The white level pattern shows patches from 1% to 10% below white. If the faint ones vanish into the white, lower the contrast until they come back. On a well set screen you see every patch, or all but the faintest one or two. Tap the faintest one you see to record it.

Then check gamma: step back, squint, and find the patch in the middle of each lined block that blends in. 2.2 is the PC and web standard.

Banding, 8 bit and 10 bit

Banding is visible steps in a fade that should be smooth. An 8 bit signal has 256 levels for each of red, green and blue; 10 bit has 1,024. The browser draws these gradients with 256 levels, so on a wide screen each level is a band a few pixels wide, and very faint, even steps are normal.

Bands that are wide, uneven or tinted point elsewhere: a 6 bit panel, a color profile or night light mode, a picture mode on a TV, or a cable or setting that lowers the color depth. Because the browser draws 256 levels, this test cannot tell an 8 bit panel from a 10 bit one.

Sharpness and scaling

The sharpness pattern draws lines one and two screen pixels wide, a checkerboard and text from 9 px to 20 px. At native resolution the one pixel lines look like an even, fine gray texture up close, and the text is crisp.

Blur, waves (moiré) or uneven lines mean the picture is being scaled: a resolution that is not native, browser zoom, or Windows scaling such as 125%, which is shown as a pixel ratio of 1.25 under the patterns. Light halos around text mean the screen's sharpness setting is too high.

Troubleshooting and privacy

If full screen does not open, the test fills the window instead. Faint glow at the edges on black is likely backlight bleed: check it with the backlight bleed test. Faint shapes on gray can be burn-in: use the screen burn-in test.

Everything runs on your device and nothing is sent anywhere. Your picks stay in this tab and are gone when you leave or reload.

FAQ

Can I calibrate my monitor with this test?

You can set brightness, contrast and gamma by eye, which fixes the most common problems. Exact color calibration needs a hardware colorimeter and its software.

Why do I see bands in the gray gradient?

Faint, even steps can be normal: the browser draws 256 levels, so each step is a few pixels wide on a large screen. Uneven, wide or tinted bands point to the panel, its settings or a color profile.

Does this test work on a laptop, phone or TV?

Yes. On a phone, iPhone Safari cannot go full screen, so the test fills the window. On a TV, use its browser or connect a laptop with HDMI.

What gamma should my monitor have?

2.2 for normal PC and web use, which matches the sRGB standard most content is made for. Some screens have a gamma setting in their menu; pick the one where the 2.2 patch blends in.

Why are the fine lines gray or wavy?

The screen is scaling the picture. Set the native resolution, set browser zoom to 100%, and turn off any sharpness or overscan setting on a TV.

All display tests

Dead pixel test
Fill the screen with colors, mark dead or stuck pixels and try the fixer.
Backlight bleed test
Check an LCD screen for light leaking at the edges and IPS glow.
Screen burn-in test
Find burned-in logos and taskbars on OLED and plasma screens.

Maintained by NabeelUpdated Oct 20, 2026.