This monitor test provides a set of full-screen test patterns for judging the quality of any display. Smooth gradients reveal colour banding, grids and geometry patterns expose sharpness and alignment issues, and colour bars let you check that red, green, blue, white and grey render cleanly. It is a practical way to evaluate a new monitor, compare two screens, or dial in your settings, all from the browser without installing anything.
The gradient patterns are the quickest way to see banding, the visible steps that appear when a panel or its settings cannot render a smooth transition between shades. On a good display the gradient looks continuous, while a weaker panel or an aggressive contrast setting breaks it into distinct bands. Grey gradients also help you check that shadow and highlight detail are not being crushed: you should be able to make out the darkest and lightest steps rather than seeing them collapse into pure black or white.
Grid and geometry patterns test sharpness, focus and alignment. Fine lines should stay crisp from edge to edge, and a grid should look even across the whole screen rather than stretching or blurring toward the corners. These patterns also make backlight bleed and clouding easier to see on a dark field, and they help you confirm that a screen is running at its native resolution, since a mismatched resolution makes thin lines shimmer or appear uneven. Colour-bar patterns round out the set, letting you confirm each primary colour is pure and that whites are neutral rather than tinted.
All the patterns display full screen so nothing competes with the image, and you move between them with a click or the arrow keys, exiting whenever you like with the on-screen button or the Escape key. The test runs entirely in your browser with no downloads, which makes it a convenient tool for checking a monitor in a shop, verifying a second-hand display before you buy, or simply making sure your own screen is set up well.
How this test works
This test draws each pattern with CSS gradients and repeating gradients rather than images or canvas, which keeps them exact at any resolution and costs almost nothing to render. The Fullscreen API removes every piece of browser and page chrome, because a toolbar in view makes one corner of the screen untestable. As with the dead pixel test, nothing is measured here: each pattern is a visual aid designed to make one specific class of defect visible.
How to use the monitor test
- Set your display to its native resolution for the most accurate results.
- Start the test and enter full-screen mode.
- Cycle through the gradient, grid and colour-bar patterns with a click or the arrow keys.
- Check gradients for banding, grids for sharpness, and colour bars for pure colour.
- Exit with the on-screen button or the Escape key when you are finished.
Reference tables
These are server-rendered, so they are readable without running the test and quotable without running any JavaScript. Where a figure comes from a specification it is cited under the table; where it is our own judgement, the table says so.
| What it measures | What it cannot see |
|---|---|
| Render banding, grid, checkerboard and uniformity patterns at full screen | Measure anything: every pattern here is a visual aid, not an instrument |
| Reveal backlight bleed and IPS glow on a solid black field in a dark room | Distinguish the two; bleed changes with viewing angle, glow does not, and only you can see that |
| Show scaling and sharpness problems through a one-pixel grid | Tell you whether the cause is the panel, the cable, the GPU scaler or browser zoom |
Compiled by MyGearCheck from the browser APIs each test uses. Every limit listed here is a limit of the browser, not of your hardware.
| Pattern | What it reveals | What to look for |
|---|---|---|
| Grey gradient | Colour banding | Visible steps or bands instead of one smooth ramp |
| RGB gradient | Per-channel banding and tint | Steps in one colour channel but not the others |
| Colour bars | Colour accuracy and clipping | Bars that look muddy, shifted or merged into their neighbour |
| One-pixel grid | Scaling and sharpness | Lines that shimmer, thicken or disappear in places |
| Checkerboard | Overdrive and inverse ghosting | A shimmer or crawl in a pattern that should be perfectly still |
| Solid white | Uniformity and dirty-screen effect | Darker or warmer patches, usually towards the corners |
| Solid black | Backlight bleed and IPS glow | Light leaking from the edges (bleed) or a corner haze that shifts as you move your head (glow) |
Compiled by MyGearCheck from what each pattern is for. Judge the black-field patterns in a dark room: in daylight almost every panel looks clean, which is exactly why a shop demo never shows bleed.
Frequently asked questions
What is colour banding and how do I spot it?
Colour banding is visible stepping in what should be a smooth gradient. Display a gradient pattern full screen: if you see distinct bands rather than a continuous blend, the panel or your current settings are struggling to render the full range of shades.
How do I check for backlight bleed?
Use a solid black or dark pattern in a dark room and look at the edges and corners of the screen. Uneven brighter patches are backlight bleed or clouding, most common on LCD panels with edge lighting.
Why do the grid lines look uneven or shimmery?
Thin lines shimmer when the display is not running at its native resolution and has to scale the image. Set your operating system to the monitor native resolution and the grid should look crisp and even across the whole screen.
Which pattern should I start with?
Solid black in a dark room. It reveals backlight bleed and stuck pixels, the two things that are invisible under any other condition and the two most people never check.
Do I need to be in a dark room?
For the black-field patterns, yes. Ambient light washes out exactly what you are looking for, which is why a monitor on a bright shop floor always looks flawless.
Does browser zoom affect the grid pattern?
Yes, and it is the first thing to check when the grid looks wrong. A grid that shimmers at anything other than 100 percent zoom is showing you the browser scaling, not the monitor.
Can this test measure response time or input lag?
No. Both need external measurement equipment, and a browser page has no way to observe when a pixel actually changed. Every pattern here is a visual aid rather than an instrument.
Why does the checkerboard shimmer?
Usually overdrive, which is the monitor pushing pixels harder to speed up transitions and overshooting. Rule out browser zoom and a non-native resolution first, because both produce a similar effect.
Guides for this test
The test shows you what is happening. These explain what to do about it.
More hardware tests
The closest tests to this one are the rest of the display group. Working through a whole machine instead? The full check runs everything in order and ends in one report.
Everything else in the suite: