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Mouse scroll test

Scroll your mouse wheel to count its steps each way and see whether it reports lines or pixels, so skips and jumps show. Free, with no account or uploads.

Scroll the wheel over the box

Scroll one way slowly: only that way's count should rise. The test says whether your wheel reports lines or pixels.

Click each button here, scroll the wheel both ways and move the mouse in circles. Click with one finger: two clicks very close together are what this test looks for.

So far

0 of 5 buttons have worked

Move the mouse in circles over the box to measure.

No button has sent two presses for one click.

Buttons that worked
0
Double-click faults
0
Wheel up / down
0 / 0
Wheel steps in
–
  • The rate counts the moves this browser hands the page; browsers can join or drop moves, above about 1,000 a second especially, so it is what reached the page, not what the mouse sends.
  • Some mice handle their side buttons themselves, and then a page never sees them.
How it works and help
Everything happens in your browser. Nothing you press is sent anywhere or kept.

A little help along the way

Follow these steps. Every option is explained underneath. Everything happens in your browser; nothing you press is sent anywhere.

  1. Choose your keyboardThe shape (ANSI, ISO, JIS, ABNT2, Korean or Mac) is guessed from your system; change it if it is wrong, and choose the size: full, tenkeyless, 75%, 65%, 60% or the number pad.
  2. Click the board and press your keysEach key lights while held and keeps a tick once it has worked. The site's own shortcuts step aside while you test. Press Escape twice to leave.
  3. Hold several at onceTo test ghosting and rollover, hold many keys together; the result keeps the most held at once.
  4. Read the resultIt says how many keys have worked, which are still to press, the most held at once, and any key that bounced.

Questions people ask

How does the scroll test work?
Scroll the wheel up and down over the box. It counts the steps each way and whether your wheel reports lines or pixels, so a wheel that skips or scrolls the wrong way shows.
Why does my wheel report pixels, not lines?
Smooth or free-spinning wheels and touchpads report distances in pixels; notched wheels usually report lines. Both are normal.
My wheel jumps the wrong way: is that a fault?
Often yes: a worn wheel sensor can send a step the wrong way. Scroll one way slowly and see whether the other count goes up.

This page is the Keyboard tester, opened for this one job; every other tool it has is one press away. Each of its settings is explained on the Keyboard tester's own page.

Read the step-by-step guide

Guides

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