Free online scroll test
Scroll Test — test your mouse scroll wheel online
Run a free scroll test to detect scroll wheel jitter, reverse scrolling, and abnormal scroll segments. This online scroll test captures every wheel event and auto-generates a visual diagnostic report so you know exactly how your mouse performs.
Start the scroll testScroll test tool
Pick a duration, hit start, then scroll your mouse wheel in one direction inside the panel below. The scroll test captures every wheel event and builds a live diagnostic report.
Press start, then scroll here (double-click also starts the test)
Scroll test panel
Duration
0
seconds elapsed
Scroll speed
0
events / second
Latest DeltaY
0
last vertical delta
Cumulative vertical
0
total vertical scroll
DeltaY max peak
0
largest positive peak
DeltaMode
Pixel (0)
pixel / line / page
Latest DeltaX
0
last horizontal delta
Cumulative horizontal
0
total horizontal scroll
DeltaY min peak
0
largest negative peak
Scroll test chart
Diagnostic report
Issues detected
No scroll events were captured yet. Start the scroll test and roll the wheel in one direction inside the test area.
Sample events
0
Reverse spikes
0
Abnormal segments
0
Total segments
0
Peak range
—
Duration
0s
Direction changes
0
Test validity
none
No direction switches were detected during the scroll test.
| Detection item | Result | Diagnostic note |
|---|---|---|
| Basic signal detection | Normal | Algorithm 1 scans for isolated opposite-direction events inserted into a consistent scroll run — the signature of a dirty or worn wheel encoder. |
| Scroll segment analysis | Normal | Algorithm 2 splits the scroll into directional segments and flags short reverse blips or erratic single-event spikes buried inside one continuous gesture. |
Sampling quality
No samples yet — start the scroll test to collect data.
Live reverse-spike count: 0. Keep at least 300 ms between consecutive scrolls to reduce false positives.
Chart analysis
The main chart plots DeltaY over time. A healthy scroll test produces a steady, same-direction line near the baseline; reverse blips show as spikes crossing the zero line.
Event detail
0 segments| # | Segment | DeltaY | Event | Interval | Reason |
|---|---|---|---|---|---|
| Not enough data yet — start the scroll test to populate the event detail table. | |||||
Three steps
How to use the scroll test
The scroll test is built for speed and clarity. Follow three simple steps to get a clean, repeatable diagnostic report you can trust.
- 1
Start the scroll test
Choose a duration — the scroll test defaults to 15 seconds — then press Start, or double-click the panel. Your scroll test begins recording wheel events immediately.
- 2
Scroll in one direction
Roll the wheel in a single direction inside the panel. The scroll test treats frequent direction switches as reverse input events and warns you, so keep the motion one-way for the most accurate scroll test.
- 3
Read the automatic report
When the countdown ends, the scroll test stops and builds a diagnostic report with metrics, a chart, and a segment-by-segment breakdown of your scroll test.
Read the panel
Scroll test metrics explained
The live panel surfaces nine metrics while your scroll test runs. Here is what each one means for your scroll test and how to read it.
- Duration
- Elapsed seconds since the scroll test started. It drives the countdown and the speed calculation.
- Scroll speed
- Wheel events received per second during the scroll test; a steady value means a consistent rhythm and a healthy encoder.
- Latest DeltaY
- The most recent vertical delta. In a healthy scroll test it stays the same sign as your chosen direction.
- Cumulative vertical scroll
- The total vertical delta accumulated over the scroll test; it should grow steadily in one direction.
- DeltaY max peak
- The largest positive peak seen during the scroll test, useful for spotting outsized or unexpected spikes.
- DeltaMode
- How the browser reports the scroll test delta — by pixel, line, or page — which affects the magnitude of every value.
- Latest DeltaX
- The most recent horizontal delta; unexpected values during a vertical scroll test hint at tilt-wheel or touch interference.
- Cumulative horizontal scroll
- Total horizontal delta over the scroll test; it should stay near zero for a vertical-only test.
- DeltaY min peak
- The largest negative peak. Deep negative peaks during a one-way scroll test suggest reverse jumps from a faulty wheel.
Under the hood
How the scroll test algorithms work
The scroll test runs two independent detection algorithms so a single noisy reading does not skew the final verdict. Both compare your wheel input against the shape a healthy scroll should take.
Algorithm 1 — basic signal reversal detection
The scroll test watches for an isolated opposite-direction event inserted into a consistent forward run — like a car briefly shifting into reverse. Steady signals draw a flat line on the scroll test chart; a sudden reverse spike points to poor encoder contact or oxidation on the wheel sensor.
Algorithm 2 — scroll segment consistency detection
The scroll test models each gesture as a smooth, hill-shaped speed curve and splits the stream into directional segments. A reverse value mixed into one continuous same-direction scroll flags that segment as abnormal in the scroll test report, separating real faults from intentional back-and-forth scrolling.
The stakes
Why run a scroll test?
The scroll wheel drives high-frequency actions all day, so a flaky wheel quietly erodes your workflow. A quick scroll test tells you whether the hardware is the culprit before you blame your browser, your document, or your game. These common scroll wheel uses are the ones a scroll test helps you protect.
Web zoom
Ctrl + scroll to zoom — a jumpy wheel makes the scroll test and your browser zoom unreliable.
Open links in a new tab
Middle-click a link; if middle input is unstable the scroll test often surfaces related jitter.
Close browser tabs
Middle-click a tab to close it, another action the scroll test helps you trust.
Horizontal scroll
Shift + scroll for lateral movement, where the scroll test checks DeltaX too.
By scenario
When a scroll test matters
Different tasks feel a bad wheel in different ways. This table maps the scenarios where a scroll test pays off and the impact you can expect when the wheel misbehaves.
| Scenario | Impact | Detail |
|---|---|---|
| Web browsing | Page scrolling is not smooth | News, forums, and social feeds all depend on a clean scroll test of your wheel. |
| Document editing | Reading and locating content is hard | Word, PDF, and Excel navigation suffers when the scroll test shows jitter. |
| Programming / code review | Code browsing efficiency drops | Jumping lines and imprecise positioning show up in your scroll test. |
| Image viewing | Cannot smoothly zoom or pan | Photoshop and image viewers lose precision — run a scroll test first. |
| Gaming | Weapon switching and view control misbehave | Mis-operations and unwanted zoom in FPS and MMO games. |
| Inertia or acceleration failure | Scroll speed is abnormal or not smooth | Unpredictable page movement distance across long pages. |
| Wheel sticking or drift | The page jumps on its own | Ghost scrolling from sensor damage or a sticky encoder. |
| 3D modeling / CAD | View control is limited | Blender and AutoCAD zoom and pan are hindered by an unreliable wheel. |
| Video and audio editing | Timeline zoom and navigation are hard | Premiere and Audition frame positioning suffers during fine edits. |
No strings
About this scroll test
Free, private, and instant. This scroll test runs entirely in your browser — no installs, no uploads, no account. Every wheel event is processed locally, so your scroll test results are ready the moment the countdown ends.
Whether you are troubleshooting a skipping wheel, comparing a new mouse before the return window closes, or just curious how your hardware behaves, the scroll test gives you a clear, repeatable reading in under two minutes. Bookmark the scroll test and run it whenever a wheel starts to feel off.
Questions, answered
Scroll test FAQ
What is a scroll test?
A scroll test is an online check that records your mouse wheel events and measures jitter, reverse scrolling, and abnormal scroll segments, then produces a diagnostic report.
How do I run a scroll test?
Choose a duration, press Start, and scroll in one direction inside the panel. The scroll test stops at the countdown and auto-generates your report.
Why does my wheel skip or reverse during the scroll test?
Common causes are a low battery on wireless mice, encoder wear, or dust in the wheel. The scroll test highlights these as reverse spikes or abnormal segments.
Does the scroll test work on phones and tablets?
No. Mobile devices lack a physical scroll wheel, and touch scrolling is fundamentally different from discrete wheel events, so the scroll test is built for desktop mice and trackpads.
How do I make my scroll test results accurate?
Scroll in a single direction and leave at least 300 ms between scrolls. A calm, one-way scroll test reduces false positives in both detection algorithms.