Which test to use
The keyboard and mouse tests read input directly in the browser, with no driver or download, which makes them useful on a new device, a second-hand keyboard or a work computer where you cannot install software.
The keyboard test draws a map of your keyboard, in ANSI or ISO layout, full size or compact. Each key lights up while you hold it and stays marked once pressed, so a key that never lights up never reached the computer. It also counts how many keys register at the same time, which shows whether a keyboard blocks key combinations in games.
The mouse test checks all five buttons and the wheel, catches a switch that bounces and double-clicks by itself, times your fastest double-click and estimates the polling rate. The scroll wheel test counts every wheel step and flags a wheel that jumps backwards, the typical fault of a worn encoder.
The clicks per second test and the space bar counter measure speed: click or press as fast as you can for a fixed time, and the best score is kept on this device. The gamepad test shows every button, stick and trigger of an Xbox, PlayStation or generic controller and lets you test vibration where the browser supports it.
How to get a reliable result
Close other apps that read the keyboard or the mouse, such as macro tools, remapping software and game overlays, because they can swallow or change input. Unplug and replug a USB device into a port directly on the computer rather than a hub. For wireless devices, charge them and keep the receiver close. A controller appears in the browser only after you press a button on it while the page is open.
When a fault is real
A fault that stays when you change the port, the cable and the computer belongs to the device. A mouse that double-clicks on its own, a key that never registers or a stick that drifts without being touched are all common warranty claims. Run the test again with the device on another computer before you send it back, and describe exactly which key or button fails.
Frequently asked questions
Which input test finds a double-clicking mouse?
The mouse test. It reports a bounce when a button is pressed again less than 40 ms after it was released, which is too fast for a human finger and the classic sign of a worn switch. Click normally for a minute; bounces that keep appearing on the same button mean the switch is failing.
Why do some keys not light up on the keyboard map?
The operating system or the browser keeps some keys for itself before a web page can see them, for example Fn, some media keys and shortcuts such as Alt+Tab or Ctrl+Alt+Del. A key that the system uses does not prove a fault. A normal letter, digit or arrow key that never lights up is the one to worry about.
Can the browser read my gaming mouse polling rate exactly?
It gives an estimate. Browsers group mouse movements, so the reading depends on the browser as well as the mouse. Chrome and Edge usually show a gaming mouse set to 1000 Hz close to that figure, while Safari reports a lower, browser-limited rate. Use it to compare settings on the same computer, not as a lab measurement.
Are my keystrokes stored or sent anywhere?
No. The tests read which keys and buttons are pressed while the page is open and the test is running, and they keep nothing after you leave. They do not record the text you type, and nothing is sent to a server. The best scores for the click and space bar counters are kept only in this browser.