Monitor Test
Gradient, black level, gamma, sharpness, uniformity and refresh-rate tests.
About this tool
Choose a pattern from the tabs and press Full screen for the most accurate view. Each pattern has a short explanation of what a good display should show. The Motion tab moves a shape across the screen and measures your refresh rate from the browser's frame timing, snapping to common rates such as 60, 120 or 144 Hz.
How to check a monitor with test patterns
Test patterns reveal display problems and settings that are hard to spot in everyday use. Gradients should run smoothly from black to white and to pure red, green and blue; visible stripes, called banding, point to a low bit-depth panel, a poor colour profile or video processing. The black level steps from 0 to 20 should show at least the steps from about 2 upwards as slightly lighter than pure black; if several merge into black, shadow detail is being crushed, usually because brightness or black level is set too low. The white saturation steps from 235 to 255 should all be distinguishable; if the brightest ones merge, contrast is too high and highlights are clipped. The gamma pattern compares solid greys with a pattern of one-pixel black and white lines, which averages to half brightness: the square that blends in shows your display's gamma, ideally 2.2 for standard sRGB content. Sharpness text and line patterns should look crisp at your native resolution and 100% browser zoom. The uniformity greys show backlight bleed, clouding and tint shifts, best seen full screen in a dark room. The motion test reveals blur and smearing and measures how often your display refreshes. Honest limits: browsers may cap the frame rate in power-saving modes or background tabs, and visual checks can't replace a hardware colorimeter for colour-critical work. For stuck or dead pixels use the dead pixel test; the screen resolution checker shows your display details.
Frequently asked questions
How do I check my monitor's refresh rate?
Open the Motion tab, keep the tab in front and wait a few seconds; it measures frame timing and shows the rate, such as 60 or 144 Hz.
What gamma should my monitor be?
2.2 is the standard for sRGB content on computers and the web.
What causes colour banding?
Low bit-depth panels, colour profile or scaling issues, and compression. A smooth gradient should show no visible steps.
Is my data saved?
No. The tests run in your browser and nothing is stored or sent.