Output
Wheel events; signed deltas; reversals
UserBenchmark / All Tools / Mouse Scroll Test
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Mouse Scroll Test
Inspect wheel direction, event count and scroll distance.
Free to useNo downloadNo sign-up
Mouse Scroll Test · At a glance
Quick answer: Inspect wheel direction, event count and scroll distance. A browser wheel delta can use pixels, lines or pages.
Mouse Scroll Test
The test loads when you open it. Device access is requested only after you choose to start.
Detailed guide
How to use this tool
- Roll the wheel slowly in one direction, reset, then test the opposite direction.
- Read the event count and signed delta.
Input
One-direction wheel movement
Browser requirement
WheelEvent.deltaMode and delta values
Processing
Runs on your device; no tool-result upload
How it works and what the result means
A reversal means the sign of the browser wheel delta changed. Delta units may be pixels, lines or pages depending on the device and browser.
Reading the result
A browser wheel delta can use pixels, lines or pages. Total delta is not necessarily the number of physical wheel notches.
What to check next
Trackpad momentum may continue after you stop touching it. Use a physical wheel and slow deliberate steps when checking an encoder.
Trackpads and momentum scrolling can naturally reverse or continue after you stop. Compare with a physical wheel before diagnosing a faulty encoder.
Frequently asked questions
Why is scroll distance different between browsers?
Browsers and devices choose different delta units and scrolling behavior. Compare the recorded delta mode and use the same device and browser.
How do I start the Mouse Scroll Test?
Move the wheel in one direction inside the test area. Check the count, direction and reversal log; reset before trying the other direction.
Does this tool require a download or an account?
No. Open the interactive tool above in a modern browser. The instructions and explanations are available even with JavaScript disabled; running a test needs JavaScript.
Why can two attempts give different results?
Power settings, background tasks, browser scheduling, operating-system input processing and device settings affect measurements. Compare repeated attempts with identical settings rather than the single highest score.