Mouse Scroll Wheel Test
Diagnose scroll jitter, reverse scrolling, and skipping. Pick a duration, hover over the area, and scroll your wheel one direction — you'll get your scroll speed, up/down counts, reverse-jitter detection, and a health verdict. Want to test the buttons too? Try the full Mouse Tester.
Scroll to start
Hover here and scroll your wheel one direction for 15 seconds.
Scroll speed over time
15s testHow it works
Scroll steadily in one direction inside the area. The first tick locks that direction and starts the timer, and from then on every wheel tick is counted and timed. Your scroll speed is the number of ticks per second, and any tick that comes back the other way is logged as a reverseevent — the clearest sign of a wheel that's misreporting. The graph shows how your speed rose and fell across the run.
What it detects
- Reverse scrolling — ticks firing opposite to the way you scroll.
- Jitter & stutter — erratic, uneven tick timing visible in the graph.
- Dead direction — one of up or down barely counting while the other works.
- Unresponsiveness — the wheel not registering ticks at all.
Fixing a faulty wheel
Most scroll faults come from a dirty or worn rotary encoder inside the wheel. Trapped dust and hair make it miss steps or send phantom ticks, so the first thing to try is cleaning it with compressed air or a little contact cleaner. If the reverse count stays high after cleaning, the encoder is probably worn out and the mouse will need a repair or replacement.
Test the rest of your mouse
Check every button and the scroll wheel together with the Mouse Tester, measure how fast your mouse reports with the Mouse Polling Rate Test, or benchmark your click speed on the CPS Test.
Frequently asked questions
How does the scroll wheel test work?
Pick a duration, then hover over the test area and scroll your wheel steadily in one direction. The first tick locks that direction and starts the clock; from there the tool counts every wheel tick, measures your scroll speed in ticks per second, and watches for ticks that come back the opposite way. When the timer ends you get a wheel-health verdict plus your totals, peak speed, and a speed-over-time graph.
What is scroll wheel jitter or reverse scrolling?
Jitter is when the wheel reports movement you didn't make — most visibly as reverse scrolling, where scrolling down briefly registers as up (or vice-versa). Because you scroll one direction during the test, any tick in the opposite direction is flagged as a 'reverse' event. A healthy wheel records zero or near-zero reverses; a steady stream of them means the wheel is misreporting, which shows up in real use as the page jumping the wrong way or stuttering.
Why is my scroll wheel jumping or skipping?
The usual culprit is the rotary encoder inside the wheel. Over time dust, hair, and worn contacts make it miss steps or fire spurious ticks, so the wheel skips, stutters, or jumps backwards. It's one of the most common mechanical mouse faults. Cleaning the encoder with compressed air or contact cleaner often helps; if the reverse count stays high after cleaning, the encoder is likely worn and the mouse may need a repair or replacement.
What's a good result?
Scroll smoothly in one direction for the whole run and a healthy wheel should report zero reverse ticks — every tick goes the way you scrolled. A few stray reverses over a long, fast session can happen and aren't necessarily a problem, but a reverse rate above a few percent, or obvious backwards jumps while you scroll one way, points to a failing wheel. Run the test a couple of times in each direction to confirm the pattern is consistent.
Does this work on a laptop trackpad?
Partly. Two-finger scrolling on a trackpad does generate scroll events, so the speed and direction counters will move, but a trackpad has no mechanical wheel or encoder to fail, so the jitter diagnosis doesn't really apply. This test is most useful with an actual mouse scroll wheel. High-resolution or free-spinning wheels also fire many small ticks, which can make the tick count climb faster than a traditional notched wheel.
Why can't I scroll the page during the test?
While your cursor is over the test area, the tool deliberately captures the wheel so your scrolling is measured instead of moving the page — otherwise the page would scroll away from the test. Move your cursor outside the area to scroll the page normally. This only affects the area itself, so the rest of the page behaves as usual.