Keyboard Tester

A keyboard tester is an online tool that detects and visualizes every key press on your keyboard in real-time. It helps you identify broken, stuck, or malfunctioning keys by showing which keys register when pressed. This is essential when testing a new keyboard before purchase, troubleshooting input problems, verifying keyboard functionality after repairs or cleaning, and checking that all keys respond correctly for gaming or professional work.

N-key rollover (NKRO) refers to a keyboard's ability to correctly register multiple keys pressed simultaneously. The "N" represents the maximum number of concurrent key presses supported. Most budget membrane keyboards handle 2-6 simultaneous keys, while quality mechanical keyboards often support full NKRO. To test yours, press multiple keys at the same time and watch the "Currently Held" and "Max Simultaneous" counters in the statistics panel. If some keys fail to register while others are held down, your keyboard has limited rollover.

A ghost key is a phantom key press that your keyboard reports even though you didn't press that key. This occurs due to the electrical matrix design of most keyboards — when certain combinations of 3 or more keys are pressed simultaneously, the keyboard may incorrectly detect a key at the intersection of the matrix lines. Our tool shows all currently registered keys in real-time on the virtual keyboard, so you can easily spot any unexpected key activations. If a key lights up that you didn't press, that's a ghost key.

These are JavaScript keyboard event properties that web developers use to handle keyboard interactions. "event.key" gives you the character value of the key (like "a" or "Enter"), which changes based on your keyboard layout and modifier keys. "event.code" identifies the physical key on the keyboard regardless of layout (like "KeyA"), making it ideal for games and hotkeys. "keyCode" is the legacy numeric code (like 65 for A) that's deprecated but still widely used. The "location" property distinguishes between left/right modifier keys and numpad keys.

Yes, this keyboard tester is 100% free with no ads, no signup required, and absolutely no usage limits. It's built with pure JavaScript and runs entirely in your browser — no keystroke data is ever sent to any server. Your key presses are processed locally in real-time and are never recorded, stored, or shared with anyone. The tool even works offline once the page is loaded. We believe privacy-sensitive tools like keyboard testers should never compromise your data, which is why we built it as a completely client-side application.