Monitor Ghosting Test
Blocks move across your screen at three speeds. Follow them with your eyes: trails behind the blocks are ghosting, bright halos are inverse ghosting from too much overdrive, and dark smears on the black background are black smearing. Use it to dial in your monitor's overdrive setting — change it, re-run, compare.
In the test: click to cycle backgrounds, ↑/↓ to change speed, Esc to exit. Judge ghosting at the speed closest to how things move in your games.
Seeing trails or halos? How to fix monitor ghosting →
How this ghosting test works
Each row shows white, gray and black blocks moving together, so you see every worst-case transition at once: dark-to-light, light-to-dark and mid-tone changes. The rows run at 0.5×, 1× and 2× the chosen speed — faster motion makes response-time problems easier to spot. The four backgrounds matter because pixel response depends on the starting color: black reveals smearing, mid-gray reveals overdrive coronas, white reveals inverse ghosting. The test renders in sync with your display (the fps counter in the corner shows the actual rate) and runs entirely in your browser.
For best results run your monitor at its native refresh rate — verify with the refresh rate test. Checking a monitor for defects? The dead pixel test covers stuck pixels and backlight bleed.
Frequently asked questions
What is monitor ghosting and what causes it?
Ghosting is a faint trail behind moving objects, caused by pixels that cannot change color fast enough to keep up with the refresh rate. It is a pixel response time problem, most visible on dark backgrounds and on VA panels. In this test it shows as a smeared tail behind the moving blocks.
What is inverse ghosting (overshoot / coronas)?
A bright or dark halo in front of or behind moving objects, in the opposite direction of the color change. It happens when the monitor’s overdrive setting is too aggressive: pixels overshoot the target color and have to come back. If you see bright edges around the blocks on the mid-gray background, lower your overdrive setting one step.
How do I fix ghosting?
Open your monitor’s on-screen menu and find the overdrive setting — vendors call it Overdrive, Response Time, Trace Free (ASUS), AMA (BenQ) or OD (LG). Start at the middle setting: too low causes ghosting, too high causes inverse ghosting. Re-run this test after each change. Also make sure the monitor is running at its full refresh rate.
What is black smearing?
A dark trail behind objects moving over dark backgrounds, typical of VA panels — pixels transitioning out of near-black are the slowest. Use the black and dark-gray backgrounds in this test to check for it. Some smearing is inherent to VA technology and cannot be fully eliminated.
Does a higher refresh rate reduce ghosting?
It reduces motion blur (each frame is on screen for less time), but ghosting itself depends on pixel response time. A 144 Hz panel with slow pixels can ghost more than a good 75 Hz panel. For the full picture, check your actual refresh rate with the refresh rate test, then judge motion clarity here.