02 Timing check
Scroll speed test
Scroll steadily for 15 seconds or more. The page counts the wheel events your browser delivered and reports events per second plus the median gap between events.
Mouse wheel test
Not tested yet01Input type
Choose “Touchpad / Free-spin” for touchpads or free-spinning wheels — coasting and inertia are normal there and the wording stays cautious.
02Test direction
03Test duration
A longer duration provides a larger observation sample. It does not make the result inherently accurate.
04Active test area
Not tested yet — press Start Test, then scroll here
waiting for input
05Live result
Live graph: no input yet. Each tick is one received wheel event; tick height reflects delta size.
Run dashboard — browser-observed values
Every value below describes events this browser delivered. Units are shown beside each metric; mixed delta units are never summed in the analysis.
| Metric | Value | Unit |
|---|---|---|
| Duration (configured) | — | s |
| Sample count (events) | — | events |
| Event rate | — | events/s |
| Latest deltaY | — | delta units |
| Accumulated vertical input | — | delta units |
| Positive / negative peaks (deltaY) | — | delta units |
| DeltaMode mix (pixel / line / page) | — | events |
| Latest deltaX | — | delta units |
| Accumulated horizontal input | — | delta units |
| Expected-direction changes | — | count |
| Possible opposite-direction events | — | events |
Observation: Result
Sample quality
Test validity
Timing profile
Timing and magnitude profile of received events — descriptive only. Event gaps are measured from browser delivery times, not hardware polling.
View event table
View run summary
Run A / Run B
What this measures — and what it does not
This scroll speed test measures browser-observed delivery: how many wheel events arrived during the timed window, and how evenly they were spaced. The dashboard on your result shows events per second alongside the median gap in milliseconds and the largest single delta.
It does not measure USB polling rate, sensor scan rate, or physical wheel notches. Browsers coalesce, smooth, and accelerate input before your page ever sees it, so two identical flicks can report different event counts in different browsers. Compare only runs made with the same browser, direction, duration, and input type.
How to run it
- Choose 15 seconds, press Start Test, and focus the pad.
- After calibration, keep one constant speed — do not speed up mid-run. Longer presets (30–120 seconds) give a larger sample for comparing wheel speed between setups.
- Read events/sec beside the median gap. A steady hand on a notched wheel usually lands in a narrow band; touchpads and free-spin wheels spread wider because of coasting.
- To test a change, save Run A, alter one condition, and record Run B with identical settings on the compare page.
Reading uneven results
Long pauses usually mean you paused, lost focus, or the tab was hidden — the timer pauses rather than inventing data. Bursts of large deltas with few events often reflect OS acceleration, not a faster sensor. Mixed pixel/line units in one run are reported separately and never summed.
Related: main scroll test · wheel jumping · how the scroll test works