Tools
Scroll wheel test
Scroll slowly in one direction. We'll catch every step and any jump the wrong way.
How the test works
Steps and direction
Each wheel notch arrives as a scroll event. We count them and flag any that go the opposite way to the rest.
Smooth and notched wheels
Trackpads and free-spinning wheels send many small steps; notched wheels send fewer, larger ones. Both are shown.
What your results mean
Reverse jumps
A few steps in the opposite direction while you scroll one way is the classic sign of a dirty or worn encoder.
Questions
Why does my scroll wheel jump up when I scroll down?
The wheel's encoder is reporting the wrong direction, usually because of dust or wear. Compressed air can help; replacement fixes it.
Does it test horizontal scrolling?
Yes. Tilt the wheel or swipe sideways on a trackpad.