Mouse test

Check every button and the scroll wheel, and find out whether your mouse is registering double clicks on its own. Nothing is installed and nothing is uploaded.

0 of 5 buttons tested

Click and scroll inside the grey area below.

Last button
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Clicks
0
Wheel steps
0
Polling rate
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Mouse events are read locally by this page to light up the diagram. Nothing is recorded or sent anywhere.

How to use the mouse tester

  1. Move the pointer into the grey area.
  2. Press each button once: left, right, the wheel itself, and the two side buttons if your mouse has them. Each one turns blue while held and green once registered.
  3. Scroll up and down to check the wheel in both directions.
  4. Move the mouse around for a few seconds and watch the polling rate settle.
  5. Finally, click the left button slowly and deliberately about twenty times, watching the click counter. It should go up by exactly one each time.

Diagnosing a double-clicking mouse

This is the fault that kills most mice, and it is worth understanding because it is easy to confirm and often cheap to fix. Inside each button is a switch with a thin metal leaf. Over hundreds of thousands of presses the leaf loses tension, and when it closes it bounces instead of making one clean contact. The computer receives two presses.

In daily use it shows up as files opening when you meant to select them, drags that drop halfway across the screen, and text that selects a whole word when you only clicked once.

The test above flags any two presses of the same button less than 60 milliseconds apart. Nobody clicks that fast on purpose, so a warning here means the switch is bouncing. One stray flag in a long session is not conclusive — several are.

What the polling rate means

Polling rate is how many times per second the mouse reports its position. Office mice typically run at 125 Hz, gaming mice at 500 or 1000 Hz, and some newer models considerably higher. A higher rate means less delay between moving your hand and the cursor moving, though the difference above 500 Hz is small for anything other than competitive gaming.

Read the number here as a rough indication. Browsers deliver mouse movements once per animation frame rather than as they arrive, so a naive count tops out around your monitor refresh rate regardless of the mouse. Where the browser exposes the grouped events, this test unpacks them to recover something closer to the true figure — but a dedicated desktop utility will always measure this better than a web page can.

Wheel problems

The scroll wheel uses a separate component from the buttons: an optical or mechanical encoder that counts rotation steps. When scrolling becomes jumpy, skips, or occasionally moves the page the wrong way, that encoder is at fault rather than any switch.

Dust is the usual cause, and a burst of compressed air into the wheel slot sometimes clears it. Persistent reverse-scrolling means the encoder is worn and needs replacing. Note that the wheel also acts as the middle button, and those two functions fail independently — a wheel that scrolls perfectly can still have a dead middle click.

When the cursor stutters or jumps

Erratic cursor movement is rarely the buttons. Check these first:

  • The surface. Optical sensors struggle on glass, high-gloss surfaces and anything with a repeating fine pattern. Put a sheet of paper down and see if the problem disappears.
  • The sensor window. A single hair across the lens is enough to cause jumping. Blow it out rather than wiping with a finger.
  • Batteries. On a wireless mouse, falling voltage causes stutter and dropouts long before the mouse dies completely.
  • Receiver distance. A USB receiver in a port on the back of a desktop, behind a metal case, is much less reliable than one at the front or on an extension.

Frequently asked questions

The counter jumps by two when I click once. What does that mean?

The switch inside your mouse is bouncing: the metal contact no longer closes cleanly, so the computer sees two presses. This is the single most common way a mouse fails. The test flags any two presses of the same button less than 60 ms apart, because no human clicks that fast deliberately.

Can a double-clicking mouse be repaired?

Usually yes. On many mice the switch can be popped open and the contact leaf cleaned or bent back, which often buys months. A proper fix is replacing the switch, a part that costs very little but needs soldering. Some manufacturers also cover this fault under warranty, so check before opening the mouse.

My side buttons do nothing here.

Browsers map the back and forward buttons to navigation, and some operating systems or vendor drivers intercept them before any page sees them. The test tries to block that, but on some setups the browser still navigates away. If the buttons work elsewhere in your system, they are fine.

How accurate is the polling rate reading?

Treat it as an approximation. Browsers group mouse movements to one per animation frame, so a plain reading tops out near your refresh rate. Where the browser supports it, the test unpacks the grouped events to recover the real count, but the result is still a rough figure rather than a measurement you should trust to the hertz.

Why is there no DPI measurement?

Because a browser cannot do it honestly. Pages see CSS pixels rather than physical ones, display scaling changes the ratio, and pointer acceleration in the operating system means the same physical movement produces different distances depending on speed. Any browser tool claiming an exact DPI figure is estimating far more than it admits.

The scroll wheel skips or jumps backwards.

That is the wheel encoder, not the switch. Dust in the encoder is the usual cause and compressed air sometimes clears it. If scrolling jumps in the opposite direction to the one you turned, the encoder is failing and needs replacing.

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