Mouse Tester
Free online mouse tester. Check every button and the scroll wheel, catch accidental double clicks, estimate polling rate in Hz, and track cursor movement.
Buttons
Click each button while the pointer is over the mouse drawing. The right-click menu is blocked inside the test area. Side buttons (back/forward) are blocked from navigating while inside the area.
Last event: none. Buttons held right now (bitmask buttons): 0
Scroll wheel
Scroll up and down with the pointer over the mouse drawing or the movement pad. Each wheel notch should count as one event.
Horizontal scroll events (tilt wheel): 0. Direction flips within 150 ms of the previous notch (possible encoder fault): 0.
Double-click test
Click the button below once, pause, then click it once again. Then try a deliberate double click. The tester shows the time between consecutive clicks and flags any pair that arrives faster than a human can click, which indicates a worn switch producing false double clicks.
A deliberate human double click usually takes 100 to 250 ms between presses. Two clicks under 80 ms apart from a single physical press almost always means switch bounce, the "double click issue" familiar to owners of ageing gaming mice. Windows' default double-click threshold is 500 ms; if your double clicks land under that but are not recognised in apps, check the mouse settings in the OS rather than the hardware.
Polling rate and movement
Move the mouse quickly in circles inside the pad for a few seconds. The tester counts how many position reports arrive per second and shows the closest standard rate.
Caveat: browsers usually merge mouse reports into one event per screen refresh, so without help a 1000 Hz mouse can read as 60 or 144 Hz. This page uses getCoalescedEvents() to recover merged reports where the browser supports it. The value is an estimate and only meaningful while the mouse is moving continuously; a stationary mouse sends no reports at all.
How to use the mouse tester
Start with the buttons. Press each one with the pointer over the mouse drawing and watch it light up while held and turn green once tested. The counters underneath tell you how many times each button registered, so you can spot a button that fires twice per press or not at all. The buttons bitmask shows which buttons the browser thinks are held right now: 1 for left, 2 for right, 4 for middle, 8 for back, 16 for forward. If it stays non-zero after you release, the mouse never sent the release event, which points to a stuck switch.
Next, scroll. Each notch of a normal wheel should produce exactly one event in the correct direction. If scrolling down occasionally produces an up event, or one notch fires two events, the optical or mechanical encoder inside the wheel is dirty or worn, a common fault that makes web pages jitter while scrolling. The "direction flips" counter catches this: humans do not reverse scroll direction within 150 ms.
The double-click section is the one most people come here for. Worn micro-switches make a single press register as two clicks, which shows up as files opening when you meant to select them and dragged items dropping halfway. Click the target slowly and deliberately; any pair flagged under 80 ms was not you.
Finally, the polling section estimates how often your mouse reports its position. Gaming mice run at 1000 Hz (one report per millisecond) or higher; office and wireless mice often run at 125 Hz to save battery. Move fast in circles and read the peak value. Distance moved is counted in screen pixels and is mostly useful for confirming that the sensor tracks smoothly on your surface: a jump of hundreds of pixels while you moved a little means the sensor lost tracking, usually because of a glossy or transparent surface, a dirty lens, or low battery.
Fixing common mouse problems
- False double clicks: update the firmware, then look in the manufacturer software for a debounce or "click delay" setting. If neither helps, the switch needs replacing; on most mice it is a standard part and a fifteen-minute soldering job, and some newer mice use optical switches that cannot develop this fault.
- A button that does not register: check for a remap in the mouse software or in the OS accessibility settings, then test on another computer. Side buttons in particular are often assigned to macros or DPI shifting by default.
- Erratic scrolling: blow compressed air around the wheel and, if you can open the mouse, clean the encoder with isopropyl alcohol. Also check the OS scroll settings and any smooth-scrolling browser extension.
- Low polling rate: many wireless mice drop to 125 Hz in power-saving mode or when the battery is low. Plug it in or change the mode in the software. Using a USB hub or a long extension cable can also cause report drops.
- Cursor jumping or stuttering: clean the sensor lens, change to a matte mouse pad, and move the wireless receiver away from USB 3.0 ports, which radiate interference on the 2.4 GHz band.
Frequently asked questions
My mouse double-clicks when I click once. What is wrong?
The micro-switch under the button has worn contacts, so a single press produces a bouncing signal that the mouse firmware reads as two clicks. It is the most common failure on mice, and well known on several popular wireless models. Use the double-click section above: if a deliberate single click is flagged as an accidental double click, the switch is failing. Fixes range from a firmware update or a raised debounce setting in the manufacturer software (masks the problem) to replacing the switch (cures it).
Why is the polling rate estimate lower than my mouse's setting?
Browsers do not deliver every mouse report to the page. Most of them coalesce movement events into one per display frame (60 to 240 per second), so a 1000 Hz mouse can read as 60 Hz. The tester uses getCoalescedEvents() where the browser supports it to recover the underlying reports, which is why the estimate is accurate in Chrome and Edge but often capped in Safari. Keep the mouse moving continuously and fast during the measurement window for the best reading.
The back and forward buttons do nothing here.
Side buttons report as button 3 and 4 in the browser, and the tester blocks their default navigation only while the pointer is inside the test area. If they still do not register, check whether the manufacturer software has remapped them to another function or to a macro; those remaps happen before the browser sees the event.
What does scroll delta mean?
Each notch of the wheel fires a wheel event with a deltaY value. On a typical mouse it is about 100 pixels per notch in Chrome and 3 lines in Firefox (shown as delta mode 1). Free-spin wheels and touchpads send many small deltas. If a single notch sometimes scrolls the wrong way or produces two events, the wheel encoder is dirty or worn.
Does this work with a trackpad or a touch screen?
Yes for clicks, scrolling, and movement, since the browser exposes them through the same pointer and wheel events. Polling rate is not meaningful for a trackpad, and touch screens have their own touch screen test on this site.
Is my click data sent anywhere?
No. Everything on this page runs in your browser with no analytics scripts, and no data leaves your device. Refresh the page to clear everything.
Last updated 2026-09-15. Everything on this page runs in your browser. Nothing you type or upload leaves your device.