Mouse tester

Check all five buttons, the wheel, and the phantom double click that gives away a worn micro-switch.

Click here

Try every button and the wheel inside this box.

Left Untested
Middle Untested
Right Untested
Back Untested
Forward Untested
Wheel up Untested
Wheel down Untested

Click chatter detector

Measures the gap between two consecutive clicks of the same button. Under 70 ms is almost never intentional — usually a worn micro-switch.

Last interval: No data yet
Suspicious repeats: 0

Generated right here, in your browser. What you type never leaves your device.

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A mouse rarely dies all at once. What usually happens is that it starts registering two clicks where you made one, the wheel jumps backwards as you scroll down, or a side button stops responding now and then. This test puts those symptoms in writing, which is what you need in order to decide between cleaning it, repairing it, or claiming the warranty.

The test works with any mouse the system recognises, wired or wireless, and needs no drivers or vendor software.

Manual

How to use it

1
Press each button inside the box

The diagram lights up the area of the button you are pressing. The five standard buttons are left, middle (the wheel), right, and the two side buttons for back and forward.
2
Scroll the wheel both ways

Steps up and down are counted separately. If a smooth scroll one way adds steps in the other, the wheel encoder is dirty or worn.
3
Make normal clicks for the chatter detector

Make about twenty separate left clicks at a normal pace. The suspicious-repeats counter should stay at zero.
4
Repeat with a different connection

If the mouse is wireless, try it wired or on another USB port too. That rules out the receiver or the port being at fault rather than the mouse.

In depth

Things worth keeping in mind

How to read the results

A healthy mouse finishes the test with every button marked, the wheel counting clean steps in both directions, and zero suspicious repeats after several dozen clicks.

A button that never responds: broken micro-switch or a snapped internal wire.
Occasional suspicious repeats: a micro-switch starting to fail; it usually gets worse.
The wheel counting steps in the opposite direction: dirty encoder.
Intermittent dropouts on a wireless mouse: low battery or interference, not a faulty button.

History

A wooden box with two wheels

The first mouse was built in 1964 by Bill English from a sketch by Douglas Engelbart, at the Stanford Research Institute. It was a pine box with one button and two perpendicular metal wheels: one measured horizontal movement, the other vertical. The cable came out of the front like a tail, which is where the name that stuck in the lab came from.

Engelbart showed it to the world on 9 December 1968, in the session now known as "the mother of all demos": ninety minutes in which he introduced the mouse, hypertext, video conferencing and collaborative editing all at once. The patent, granted in 1970 as an "X-Y position indicator for a display system", expired before mice were selling in volume. SRI ended up licensing it to Apple for around $40,000.

The rubber ball arrived with Bill English once he had moved to Xerox PARC, in the early seventies, and lasted almost thirty years until optical sensors retired it at the end of the nineties. That switch killed the maintenance ritual — popping the cover off and scraping lint from the rollers — but not the microswitch failures, which are still the number one reason anybody opens a mouse tester.

1964: The first prototype, in a pine shell with two metal wheels.
9 Dec 1968: "The mother of all demos" — the first time an audience saw a mouse working.
10–20 M: Clicks a typical microswitch is rated for. Which is why phantom double-clicks show up with use, not out of the box.

How it works

What this test is actually measuring

The browser never talks to your mouse. It talks to the operating system, which has already turned what the mouse did into events. Pressing sends a mousedown event carrying a button number — 0 left, 1 middle, 2 right, 3 and 4 for the side buttons — and releasing sends mouseup. The wheel is a separate event, wheel, carrying a deltaY that is positive or negative depending on direction.

That chain matters when reading your result. If a button does not light up here, the fault is somewhere before the browser: the switch, the cable, the wireless receiver or the driver. And the other way round, if it lights up here but still fails inside a game, the hardware is fine and the problem is configuration.

Phantom double-clicking has one specific physical cause. Inside every button sits a microswitch with two metal leaves; when they meet they bounce for a few milliseconds before settling. The mouse firmware ignores any change inside a debounce window, usually 8 to 20 milliseconds. As the leaves oxidise or lose tension with use, the bounce outlasts that window, and the firmware can no longer tell it apart from a genuine second click.

That is why this test measures the gap between presses. Two clicks less than about 40 milliseconds apart did not come from your finger — no human presses twice that fast. That pattern is what gives away a worn microswitch, and it is the evidence you need if you are going to make a warranty claim.

By hand

Confirming a worn button without software

Before buying anything, these four checks separate a dead switch from a configuration or surface problem.

1

If the phantom double-click follows it, the mouse is at fault. If it disappears, the problem lives in the driver, the USB port or the settings on the first machine.
2

USB 3.0 ports emit interference in the 2.4 GHz band — the same band nearly every wireless receiver uses. A mouse that stutters next to an external drive often stops once the receiver moves to a front port or an extension cable.
3

Squeeze the button down slowly until you hear the click, then release just as slowly. A healthy switch gives one crisp click; a worn one sounds dull or dragging, or produces two clicks from a single press.
4

If the cursor is what misbehaves rather than the buttons, try it on a sheet of opaque paper. Glass, glossy surfaces and very dark mats reflect the sensor light poorly and produce jumps that look exactly like a fault.

Diagnosis

If something is not working

Symptom:One click registers as two

Likely cause:: The microswitch is worn: its leaves bounce for longer than the firmware ignores, so the mouse reports two genuine presses. It is the most common failure, and it shows up first on the left button, which takes about 90% of the use.
What to do:: If your mouse has vendor software, raise the debounce time — many models allow 20 or 30 ms — and you will buy yourself months. Otherwise the switch can be cleaned with contact cleaner or replaced, which is a straightforward soldering job. And if the mouse is under warranty this is a covered defect: keep the result of this test as documentation.

Symptom:The wheel jumps backwards when scrolling down

Likely cause:: The wheel encoder is dirty or worn. Most are mechanical: a notched disc read by sliding contacts. With dust and wear, a notch gets read twice, or in the wrong direction.
What to do:: Compressed air first, spinning the wheel while you blow. If that is not enough, a drop of contact cleaner into the encoder followed by a solid minute of spinning fixes most cases. Mechanical encoders can also have their internal contacts re-tensioned, though that means opening the mouse.

Symptom:Side buttons do nothing in some applications

Likely cause:: This is almost never hardware. Side buttons send buttons 4 and 5, and plenty of applications simply ignore them; other times the vendor software has remapped them to a macro that does nothing in that program.
What to do:: If they light up here, the mouse is fine. Check the active profile in the vendor software, and whether the application has its own button configuration. In games, look inside the game’s own control settings rather than the system ones.

Symptom:The cursor jumps or freezes for an instant

Likely cause:: Usually the surface or interference rather than the sensor. Glass and high-gloss surfaces do not return a pattern the sensor can track, and USB 3.0 ports generate noise right on the 2.4 GHz band wireless receivers use.
What to do:: Test on opaque paper to rule out the surface. If it is wireless, move the receiver to a port away from external drives and USB 3.0 hubs, or use a USB extension to bring it closer to the mouse. If it runs on batteries, change them: many mice start stuttering well before they report a low battery.

Symptom:The button only works if I press hard

Likely cause:: The microswitch spring has lost tension, or dirt between the leaves is stopping them making contact under normal pressure.
What to do:: Contact cleaner through the switch slot, then work the button thirty or forty times to spread it. If it improves and then degrades again within weeks, the spring is done and only replacing the switch will fix it.

Trivia

Things worth knowing

The first one was wooden and had a tail

Douglas Engelbart built it in 1964 at the Stanford Research Institute: a wooden box with two perpendicular wheels. They called it a mouse because the cord trailed from it like a tail. On the first prototype it came out of the front, and it was later moved to the back because it got in the way of the hand.

Its inventor made almost nothing from it

The patent belonged to the Stanford Research Institute rather than to Engelbart, and it expired in 1987 — just before the mouse became universal. The institute licensed it to Apple for a figure repeatedly reported as around $40,000.

Contact bounce is a real physical effect

When two metal leaves meet, they literally bounce before settling. It is the same effect that forces debouncing into keyboards, industrial switches and game controllers: not a manufacturing defect, just how metal behaves.

Your sensor takes thousands of photos a second

A modern optical sensor photographs the surface between 6,000 and 12,000 times per second and compares each frame with the last to work out how far you moved. It is, quite literally, a tiny camera staring at your desk.

The scroll wheel took thirty years to arrive

The mouse dates from 1964, but the scroll wheel only reached the mainstream with Microsoft’s IntelliMouse in 1996. Before that, moving through a long document meant dragging the scrollbar with the cursor.

Questions

Frequently asked questions

What is phantom double clicking?

It is when the mouse sends two presses although you only made one. It happens because the button micro-switch wears out and its contacts bounce. You notice it when dragging files, which drop by themselves, or when selecting text.

Why is 70 milliseconds the threshold?

A deliberate human double click usually falls between 100 and 300 ms. Repeatedly going under 70 ms is faster than a hand can do on purpose, so it points at the hardware rather than the user.

The browser does not detect my side buttons — is the mouse broken?

Not necessarily. Some mice send the side buttons as keyboard shortcuts (Alt+Arrow, for example) instead of as buttons 4 and 5. In that case the browser sees a key, not a button. Check the vendor software to see how they are mapped.

Can phantom double clicking be fixed?

Sometimes. Compressed air into the button, or opening the mouse and cleaning the micro-switch with isopropyl alcohol, solves many cases. If it comes back, the permanent fix is replacing the micro-switch — a part costing under a euro, but it needs soldering.

Does this test measure polling rate?

No. Browsers batch movement events to the display refresh rate, so they cannot reliably tell whether the mouse reports at 125, 500 or 1000 Hz. That requires a desktop tool.

Is any data sent to a server?

No. Everything on this page is processed in your browser and disappears when you close it or press Reset.