Check the connection and selected device, then repeat the failed check: the target does not advance.
Part of the Mouse test. Run the full mouse test first for a complete device check.
The target does not advance Results vary widely The value exceeds another utility
Mouse latency test
Measure click-to-paint delay over repeated targets and report median, tail and uncertainty values.
Also known as: mouse latency test, click latency test, mouse input lag test, click delay test. Free, online, and no download required.
No permission neededNothing uploaded
Press the target when it appears to begin collecting samples.
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What the mouse latency test checks
| Check | How it is measured | Fails when |
|---|---|---|
| Input timestamp | The pointer event timestamp anchors each sample. | The browser supplies an invalid or repeated timestamp. |
| Paint completion | Two animation frames bound the next visible paint opportunity. | A sample never reaches the paint callback. |
| Distribution | Median, 95th percentile and median absolute deviation summarize the set. | Fewer than ten valid samples arrive. |
If something failed
Check the connection and selected device, then repeat the failed check: results vary widely.
Check the connection and selected device, then repeat the failed check: the value exceeds another utility.
02
How to read the result
How the mouse latency test works
Each pointerdown stores its browser event timestamp and schedules two animation frames. The second callback records the elapsed click-to-paint interval, then moves the target. A pure percentile probe calculates p50, p95 and median absolute deviation without sorting the live array on every event.
What the result can establish
Keep the tab foreground, avoid moving the window during the run and collect at least twenty targets. Compare repeated distributions on the same browser and display mode.
Measurement limits
This measurement includes browser dispatch, JavaScript, style, layout, rendering and compositor scheduling. It is not a direct sensor, USB or display-panel delay.
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Mouse latency test questions
What does this mouse input lag test actually measure?
It measures click-to-paint: the interval from the pointer event timestamp to the next visible paint opportunity, bounded by two animation frames. That covers browser dispatch, JavaScript, style, layout and compositing, and nothing below the browser.
Why is my click latency test result higher than a review's?
Hardware reviews measure sensor-to-photon with external equipment and exclude the browser entirely. This result includes an entire rendering pipeline, so a larger absolute number is expected. Compare runs against each other on the same machine, not against published hardware figures.
How many samples should a click delay test collect?
At least twenty targets, with the tab in the foreground and the window still. The summary reports median, 95th percentile and median absolute deviation, because a single sample can be shifted several milliseconds by unrelated scheduling work.