This check can be useful when you are evaluating a new or secondhand display, or trying to understand a motion issue you have noticed in everyday use. Clean the screen and sit at your usual viewing distance so smudges or an unusual viewing angle are less likely to distract from what you see.
How to use Response Time Test
- Select Start Test to open the test in fullscreen. You can also use the Fullscreen button or press F to toggle fullscreen.
- Set Target speed to 120 CSS px/s, 240 CSS px/s, or 480 CSS px/s. Pattern mode is Moving gray transitions.
- Select Start motion to begin the moving targets. Compare how the dark-to-light transitions appear at each speed, changing one speed at a time.
- Use Space to start or pause the motion, or choose Start motion when you want to begin. Press R or select Reset to reset the page.
- Press Escape to exit fullscreen, or select Exit fullscreen if that control is shown.
When to use it
- Checking a new monitor before the return period ends: Look for conspicuous trails or blur while the gray targets move.
- Inspecting a used display before buying: Add a motion check to your basic visual inspection.
- Comparing display settings: View the same target speed before and after changing a setting on the monitor, then compare what is visible.
- Investigating blur in games or video: See whether moving gray transitions also look unclear in this simple test.
- Checking a complaint that appears only at faster motion: Compare the three available target speeds to see whether the appearance changes.
- Rechecking after moving or reconnecting a display: Use the same visual pattern to see whether an apparent motion issue remains.
Tips for a clearer comparison
Compare one speed at a time and keep your viewing position and room lighting consistent. If you are comparing monitor settings, change only one setting between checks; otherwise, it can be difficult to tell what caused a visual difference.
Watch the moving gray transitions at a comfortable pace. Frame pacing, eye tracking, and display processing all influence how motion appears, so use what you see as a practical comparison rather than trying to assign a precise number. If the animation is paused, start it explicitly before judging the motion.
Keep the display's own picture settings the same when comparing two screens. This makes the visual difference easier to interpret, although it still does not make the result a calibrated measurement.
Limits of the Response Time Test
The Response Time Test is a visual reference, not a millisecond pixel-response measurement. Browser animation timing, how smoothly frames appear, eye movement, and the display's processing can all affect the result. A visible trail can be a reason to investigate further, but this test cannot identify its cause or certify a display's specifications.
If a problem is persistent or disruptive, check the display using your usual content and consult the seller or manufacturer. For another view of motion artifacts, try the Ghosting Test; for a broader visual check, use the Monitor Test.