Measure Your Scroll Speed
Use your mouse scroll wheel in the test area. Track real-time scroll velocity, peak speed, and acceleration — all processed locally in your browser.
This test captures wheel events and measures deltaY per event (lines or pixels), peak scroll velocity, total accumulated distance, and smoothness score based on event interval consistency.
Standard notched scroll wheels produce deltaY of ~100px per tick, while free-spinning wheels (e.g., Logitech MX Master) can produce 500+ px/event at high speeds.
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What Do Your Results Mean?
| Result | Range | Meaning |
|---|---|---|
| Good | Consistent deltaY, smooth event intervals | Your scroll wheel produces even, predictable values across events — ideal for precise scrolling in documents, code editors, and games. |
| Warning | Occasional irregular deltaY or missed events | Inconsistent values may indicate dust in the scroll encoder or OS-level scroll acceleration distorting raw values. Clean the wheel gap or disable OS scroll acceleration. |
| Bad | Scroll direction reversal or no events detected | Direction reversal (scrolling down registers as up) indicates a failing encoder. No events at all suggests a broken scroll mechanism or driver issue. |
Common Issues and How to Fix Them
Scroll direction randomly reverses
The rotary encoder inside the scroll wheel is likely dirty or worn. Compressed air blown into the wheel gap can help. If the problem persists, the encoder needs replacement.
Scroll speed feels different in the test vs normal use
OS-level scroll acceleration multiplies raw deltaY values. The test shows raw wheel events — disable 'smooth scrolling' in browser settings and OS mouse settings to compare raw hardware output.