Mouse Scroll Test

Test scroll wheel direction, speed, and step consistency — including delta timing and mechanical encoder glitching.

Wheel: Idle
Steps0
Velocity
0L/s
Peak
0L/s
Glitches
0

Scroll Up or Down Here

Continuous scrolls in one direction will detect loose rotary contacts and reverse step stutter.

0 L/sVelocity Gauge250+ L/s
Last Delta: 0 px
Accumulated: 0 px
Scroll Event Stream0 events
Normal ScrollReverse Glitch / Skip
No scroll events recorded yet. Scroll inside the box above to inspect encoder wheel ticks.
Encoder Science

Understanding Scroll Wheel Rotary Encoders

Mechanical Rotary Encoders

TTC / ALPS / Kailh

Mechanical encoders rely on internal metallic wiper pins stepping across a conductive wheel track. Over time, oxidized lube and dust cause phase signal misreads, leading to reverse scroll jumps.

Optical Wheel Encoders

Glitch Resistant

Optical encoders (used in select tournament mice) project an infrared beam through a spoked wheel. Contactless optical tracking makes them far less prone to reverse scroll jitter and mechanical wear.

Delta Y Steps

Browser API

Standard notch steps report a deltaY magnitude of ±100 or ±120. Consistent direction without sign reversals confirms encoder health.

Free-Spin Smooth Scrolling

Infinite Scroll

Feature-rich mice (Logitech Hyper-Scroll, Razer SmartWheel) unlock detent tactile tension, enabling high-velocity smooth scrolling across long documents.

FAQ Reference

Scroll Wheel Diagnostic Frequently Asked Questions

Why does my scroll wheel jump in the wrong direction?
Worn or dust-clogged rotary wheel encoders produce noisy optical/mechanical signals, causing reverse scroll jumps during scrolling.
What does the mouse scroll test measure?
The test measures vertical and horizontal delta offsets, instantaneous scroll speed in pixels per second, and verifies whether wheel notches (steps) fire in the correct directional sequence.
How can I fix a mouse scroll wheel that jumps or stutters?
In many common instances, blowing compressed air into the wheel housing clears dust, pet hair, or debris obstructing the optical or mechanical encoder wheel contacts. If the internal rotary encoder contacts are physically oxidized or worn down, cleaning contacts with isopropyl alcohol or replacing the encoder switch is necessary.
What is the difference between mechanical and optical scroll encoders?
Mechanical encoders use internal wiper pins making physical contact with electrical contact plates as the wheel turns. Optical encoders use an infrared LED beam shining through spoked wheel blades, eliminating physical contact wear and reverse scroll jumping.
Can mouse wheel debounce cause missed scroll inputs in games like Apex Legends?
Yes. Many players bind 'Jump' to scroll wheel down for bunny hopping or tap strafing. If mouse firmware debounce filters wheel clicks too aggressively, rapid scroll ticks can be throttled by the controller.