Refresh Rate Test
Check the refresh rate your screen is running at, in Hz, and see how smooth that rate looks.
Ghosting and Motion Blur Test
Watch blocks, bars, text or fine lines move across your screen at a speed you choose, and look for ghosting trails, motion blur and overdrive halos by eye. The pattern runs on the page or full screen.
The Bars and Lines patterns move high-contrast stripes across the screen and can flicker at higher speeds. Do not use them if you are sensitive to flashing lights or striped patterns, and pause the test or lower the speed if it bothers you.
Showing Blocks · 600 px/s
Follow one square with your eyes. A faint copy trailing behind it is ghosting; a bright or dark fringe along its edges is an overdrive halo.
Pixels per second. Faster motion makes trails longer and easier to see; slower motion makes sharpness easier to judge.
Measuring frame rate…
Runs entirely in your browser. Test results, audio and video never leave your device.
How to test your monitor for ghosting
- Pick a pattern: Blocks for trails and halos, Bars for smeared edges, Text for readability in motion, Lines for overdrive halos.
- Set the Speed slider, from 100 to 2000 px/s (600 by default). Faster motion makes trails longer; slower motion makes sharpness easier to judge. The slider is only on the page, so set it before going full screen.
- Press Start test, or click the preview, to fill the screen, then follow one moving shape with your eyes.
- Press Invert for black shapes on white. Trails and halos can look different on a light background.
- In full screen, change pattern with Next, the arrow keys, Space or a tap. Pause freezes the motion, and Esc exits.
- Check the frame-rate line under the Speed slider. It should be close to your refresh rate, which the Refresh Rate Test estimates.
What is monitor ghosting?
Monitor ghosting is a faint trail behind a moving object, left because the screen's pixels take too long to change from one shade to the next. It comes from the panel and its overdrive setting, not from the computer, and it gets easier to see as motion gets faster. Overdrive halos and motion blur look similar but have different causes.
Ghosting vs inverse ghosting vs motion blur
| Artifact | What you see | Usual cause and what helps |
|---|---|---|
| Ghosting | A faint trail or copy behind the moving shape | Slow pixel response. Raise overdrive one step at a time. |
| Inverse ghosting (overshoot) | A bright or dark halo along the edges, sometimes tinted | Overdrive set too high, so pixels go past the target shade. Lower it one step. |
| Motion blur | The whole shape looks soft as your eyes follow it, with no separate trail | Each frame stays on screen until the next. A higher refresh rate or a backlight strobing mode reduces it; strobing pulses the backlight on purpose, a form of screen flicker. |
| Dark smearing | Long dark trails behind shapes in dark scenes | Slow near-black transitions, typical of VA panels. Overdrive can reduce it but rarely removes it. |
| Stutter | The shape jumps instead of gliding | Dropped frames in the browser or game, not the panel. |
How to find the right overdrive setting
- Open the monitor's on-screen menu and find the overdrive setting. Makers name it differently, for example Overdrive or Response Time.
- Choose Blocks, set Speed to about 1000 px/s and press Start test.
- Step through each overdrive level. Trails get shorter as it rises; too high adds a bright or dark halo.
- Keep the highest level that shows no halo, then check again with Invert on.
- Repeat at each refresh rate you use. Overdrive can behave differently at lower rates, especially with FreeSync or G-Sync.
What this test can detect
- Ghosting: a faint copy or trail behind a moving square or bar.
- Overdrive halos (inverse ghosting): a bright or dark fringe along the edges of a moving shape, sometimes tinted.
- Soft or smeared edges between moving bars, from slow pixel transitions.
- Motion blur: moving text that turns soft or unreadable as you follow it.
- Stutter from dropped browser frames, shown by a frame rate below your refresh rate.
How it works
The page draws each pattern on a canvas at your screen's full pixel density, up to 3 device pixels per CSS pixel, with every block, bar and line on whole device pixels, so scaling does not soften their edges. Shapes move by time, not by frame: 600 px/s is 600 CSS pixels a second at any refresh rate, a 5 px step per frame at 120 Hz.
Shapes are white on black, or black on white with Invert, and the blocks have a 1 px mid-gray outline. The frame-rate line counts the frames the browser drew in the last second.
Limitations
- A browser cannot measure response time, MPRT or input lag. You judge trails and halos by eye, and what you see depends on how smoothly your eyes follow the shape.
- The patterns are black and white, with a thin gray outline on the blocks. Overdrive halos and VA dark smearing show most on gray-to-gray changes, so they can look milder here than in games and films.
- The Bars and Lines patterns move high-contrast stripes and can flicker at higher speeds. Skip them if flashing lights or striped patterns bother you. If your system asks for reduced motion, the test starts paused.
Frequently asked questions
Can an online test check response time in milliseconds?
No. Response time (gray-to-gray) and motion blur (MPRT) figures come from a light sensor or a pursuit camera, which is how reviews test them. A browser can show the motion but cannot time how fast a pixel changes.
Does OLED have ghosting?
Very little. OLED pixels change far faster than LCD pixels, so trails and overdrive halos are rare, though some OLED phones smear slightly when near-black areas move. Moving objects still look soft, because each frame stays on screen until the next; a higher refresh rate reduces that blur.
Is this the same as the UFO test?
No. The UFO test is TestUFO by Blur Busters, a larger set of motion tests whose ghosting test also supports pursuit camera photos of motion blur. This page is a simpler visual check. For photos you can compare with reviews, use TestUFO's ghosting test.
Why is my monitor ghosting?
Usually because overdrive is low or off, or the panel is slow in some transitions, as VA panels are in dark scenes. Running below the top refresh rate adds blur that looks similar. Work through the overdrive steps above and confirm the rate with the Refresh Rate Test.
Why does the moving pattern stutter?
Usually because the browser is dropping frames, which is not ghosting. If the frame-rate line reads well below your refresh rate, close other tabs, plug in a laptop and try again; the shape should then glide at an even speed.