Display Response Time Test

What is this tool?

Response time is how long a pixel takes to change from one colour to another. This test drives deliberate transitions — dark to bright, bright to dark, colour to colour — at intervals you control, so you can see whether the panel keeps up or leaves something behind.

The engine implements twelve transition patterns plus directional wipes and an automated eight-step sequence, so a full inspection does not depend on you remembering which transitions you have already looked at.

What it reports is what you observed, plus the browser's own frame timing. It does not and cannot produce a millisecond GTG figure — the page devotes an entire section to that point.

How to use it

1. Choose a presetStandard is the balanced setting. Precision (Slower) holds each state longer, which makes a slow transition easier to see. Stress (Fast) switches quickly, which is where trailing becomes obvious. Comparison places conditions side by side.
2. Set the transition interval50, 100, 250, 500, 1000 or 2000 ms. Long intervals let you study the settled colour; short intervals reveal transitions that have not finished before the next one starts. Both are useful — start long, then shorten.
3. Pick a transition directionLeft → Right, Right → Left, Top → Bottom, Bottom → Top, Center → Out and Out → Center. A directional wipe puts changed and unchanged areas next to each other, which makes a lagging transition much easier to spot than a whole-screen flip.
4. Test dark and bright transitions separatelyThe page has separate sections for both, and for good reason: on many panels, particularly VA, dark transitions are much slower than bright ones. Black-to-white and white-to-black behave differently and should be judged separately.
5. Record what you sawThe labels are “Transition appears clean”, “Object edges remain sharp”, “No visible trailing”, “Slight trailing visible”, “Color change appears delayed”, “Dark transitions appear slower”, “Bright transitions appear slower”, “Motion becomes smeared” and “Double-image effect visible”. Pick every one that applies — the combination is the finding.

What the results mean

Crisp edge, clean field

The transition completes before you can register it and the settled colour is even. That is the outcome you want, and the page names it explicitly as one of the three things to look for.

Dark trailing or smearing

A dark shadow lingers behind the change. This is the panel's slow dark transition, most familiar as black smearing on VA displays. Raising overdrive one step often reduces it.

Bright halo or inverse ghosting

A light edge appears where the change happened. That is overshoot: overdrive pushing pixels past their target value. The fix is to lower overdrive, which is the opposite of the fix for dark trailing — hence the value of telling them apart.

Colour change appears delayed

The transition is visible as a process rather than an instant. Some colour pairs are slower than others on every panel, so test several before concluding the display as a whole is slow.

What the FPS readings mean

The frame numbers shown alongside come from the browser's own animation timing, exactly as in the Display FPS Test. They tell you whether the transitions were delivered on a steady cadence — they are not a measurement of pixel response.

What it can detect

• Trailing and smearing on dark transitions
• Overshoot and inverse ghosting from overdrive that is set too high
• Colour pairs that transition noticeably more slowly than others
• Double images during rapid transitions
• Whether changing the monitor's overdrive or response-time setting made a visible difference

Limits worth knowing

A browser can only report what the platform gives it. These are the honest boundaries of this page, so a result is never read as more than it is.

• The page has a section headed “14 · Why Browser Tests Cannot Measure Physical GTG” and another headed “15 · When Professional Hardware Testing Is Needed”. Both say the same thing this documentation says: no millisecond GTG figure is produced here, and none can be.
• It cannot measure MPRT either — the page's FAQ asks that directly. MPRT requires a pursuit camera or a photodiode rig.
• A manufacturer's “1 ms” claim usually refers to a single best-case transition at a specific overdrive setting. This test cannot verify or refute that number; it can only show you what the panel looks like in use.
• Your perception, ambient light and viewing distance all affect the result, which is why the outputs are descriptive labels rather than a score.

Tips

• Run the whole test once per overdrive level in your monitor's menu. The best setting is the one with the least trailing and no visible halo — and it is often not the highest one.
• Use a long interval to check the settled colour and a short interval to check the transition. They answer different questions.
• Test at the refresh rate you actually use. Response requirements tighten as refresh rate rises, because each frame gives the pixels less time to finish.

Troubleshooting

Related documentation

• DisplayScreen Ghosting TestHigh-contrast moving patterns that make trails and overshoot easy to see.
• DisplayMotion Blur TestMoving patterns at controlled speeds, so you can judge how sharp motion stays.
• DisplayRefresh Rate TestEstimate your display's refresh rate from frame timing, with a confidence level attached.
• DisplayDisplay FPS TestMeasure the frame rate your browser is actually delivering, with 1% lows and jitter.
• DisplayDead Pixel TestFull-screen solid colours for finding dead, stuck and hot pixels by eye.