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Test your monitor with test patterns

Check banding, black and white levels, uniformity, sharpness and motion blur with full-screen test patterns drawn pixel for pixel in your browser.

Arrow keys change the pattern. Esc ends the test.

Before you judge a monitor

  • Let it warm up for 15 to 30 minutes; backlights and colors drift while cold.
  • Use the panel's native resolution and, for sharpness, 100% or 200% scaling.
  • Turn off dynamic contrast, eco modes and automatic brightness, which change the picture as you look.
  • Dim the room for the black level and uniformity patterns, and look from straight in front.

Keyboard shortcuts

F
Start or leave full screen
←→
Previous or next pattern
1–7
Jump to a pattern
↑↓
Change the pattern's setting
Space
Pause the motion test

Pattern

Smooth ramps should show no stripes. Visible steps point to a 6-bit panel, a reduced color depth or heavy picture processing.

Steps per ramp (256 is smooth)
Runs in your browser · no uploadHow it works

How to use Monitor test

  1. 1

    Prepare the monitor

    Let it warm up, use its native resolution, turn off dynamic contrast and eco modes, and dim the room.

  2. 2

    Open the patterns full screen

    Press Show patterns full screen or F, then use the arrow keys or 1–7 to move between the seven patterns.

  3. 3

    Adjust each pattern

    Use ↑ and ↓ to change the gradient steps, the uniformity grey or the motion speed, and read the hint for what a good result looks like.

  4. 4

    Fix what you can in the monitor's menu

    Tune brightness, contrast, sharpness or overdrive while the matching pattern is on screen, then check again.

Limits and Pro

Free with no sign-up: seven test patterns, gradients in 16 to 256 steps, three motion speeds and a refresh rate estimate, at any screen resolution.

Pro removes the ads; the monitor test has no paid features. See Pro

About Monitor test

Test patterns turn vague impressions about a monitor into things you can check: are dark greys visible, is the backlight even, do moving objects smear? This page draws seven of them on a canvas sized in device pixels, so one pattern pixel is one pixel of your panel, and shows them full screen.

Gradients sweep grey, red, green and blue through all 256 levels of an 8-bit channel, or in 64, 32 or 16 steps for comparison; stripes in the smooth ramp mean banding. The black level chart shows squares from 0 to 20 on black and the white level chart squares from 235 to 255 on white, which reveals crushed shadows or clipped highlights. Uniformity fills the screen with 25, 50 or 75 % grey to expose clouding and dark corners. The sharpness pattern combines a 1-pixel checkerboard, 1-pixel lines and text from 9 to 16 pixels high, and color bars in the style of the broadcast SMPTE chart check color and near-black separation.

The motion test moves a block at 480, 960 or 1920 pixels a second and estimates the refresh rate from the browser's frame timing. Use it to see ghosting, blur and overshoot, and to confirm that a 120 or 144 Hz mode is active; the number reflects what the browser paints, which can be lower than the panel's maximum.

Patterns are shown in standard dynamic range only, and none of them calibrates a display: accurate color needs a colorimeter. Fractional scaling such as 125 % blurs the 1-pixel patterns, so use 100 % or 200 % when judging sharpness.

Privacy

The test patterns are drawn by the page on a canvas in your browser, and nothing is uploaded or measured remotely. The refresh rate estimate is worked out from frame timing on your device and is neither stored nor sent.

Features

Banding gradients

Grey, red, green and blue ramps through all 256 levels, or in 64, 32 or 16 steps.

Black and white levels

Squares 0–20 on black and 235–255 on white for crushed or clipped detail.

Pixel-exact sharpness

A 1-pixel checkerboard, lines and 9–16 px text drawn at device resolution.

Motion and refresh rate

A moving block at three speeds with a measured frames-per-second readout.

Monitor test: frequently asked questions

What causes banding in the gradient test?
Banding is visible stepping where a ramp should be smooth. It comes from a panel that shows only 6 bits per channel, from color depth or HDR settings in the graphics driver, from heavy picture processing such as dynamic contrast, or from a video signal with limited range. Steps in the 16- and 32-step versions are expected; in the smooth ramp, a good monitor shows a continuous blend.
How many black level squares should I be able to see?
On a well-adjusted monitor in a dim room you should tell most squares apart from about 2 or 3 upwards, each a little lighter than the last. If the first five or more vanish into black, raise the brightness or the black level setting. If even square 0 looks grey rather than black, the black level is set too high or the panel is an LCD with limited contrast.
Is the refresh rate shown my monitor's real refresh rate?
It is the rate at which the browser draws frames, measured from the timing of each frame. It usually matches the active refresh rate, so it is a quick way to check that a 120 or 144 Hz mode is really in use. It can read lower when the browser throttles animation, the computer is busy, power saving is on or variable refresh is active.
Can I test HDR with this page?
No. Web pages draw canvas content in standard dynamic range, so these patterns test the SDR picture that most desktop work uses. HDR brightness, tone mapping and local dimming need HDR test videos, or the calibration apps built into operating systems and consoles, played in a mode the display recognizes as HDR.
Why does the sharpness pattern shimmer or look blurry?
One-pixel patterns only look crisp when every pattern pixel lands on exactly one panel pixel. Fractional display scaling such as 125 % or 150 %, a resolution below the native one, or browser zoom other than 100 % resamples the pattern and creates blur or moiré. Set the native resolution and 100 % or 200 % scaling before judging sharpness or the monitor's own sharpness setting.

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