What Is Response Time?
Response Time (Pixel response time, GtG): How long a display's pixels take to change from one colour to another, usually measured grey-to-grey (GtG) in milliseconds.
Definition
Response time is how quickly a pixel can change colour, measured in milliseconds. The common figure is GtG (grey-to-grey): the time to move from one shade of grey to another.
Why It Matters
If pixels change slower than the screen refreshes, the previous image lingers and moving objects leave a trail — ghosting. At 144 Hz a new frame arrives every 6.9 ms, so pixels need to settle in roughly that time or less to keep motion clear.
GtG vs MPRT
- GtG measures how fast the pixel itself changes.
- MPRT (moving picture response time) measures how blurry motion looks to your eye, which also depends on how long each frame is held on screen. Backlight strobing modes lower MPRT.
Advertised values like “1 ms” are usually best-case figures at the most aggressive overdrive setting, which can cause bright halos called overshoot.
Check It Yourself
The ghosting test shows moving blocks on dark, grey and light backgrounds so you can see trails and overshoot, and choose the best overdrive setting.
Measure It
Related Guides
- 60Hz vs 144Hz vs 240Hz – Which Refresh Rate Do You Need?A higher refresh rate makes everything on screen look smoother. Here's how big the jumps really are, and what it takes to use them.
- How to Check a Used Monitor Before BuyingTen minutes of checks can save you from buying a screen with dead pixels, a weak backlight or a refresh rate that never works. Here's exactly what to test.
Related Terms
Part of the TapTest glossary · More in display tests.