Keyboard Tester
Press every key on your keyboard. Keys light up while pressed and stay green once they've worked, so you can spot dead keys quickly.
What the tester can and can't see
Browsers report each key with a physical code (KeyQ, Digit1, ShiftLeft…) and the character it produces. The tester lights up keys by physical position, so it works on any layout. Keys outside the standard US layout, like extra media keys or the ISO key next to left Shift, are listed under “Other keys detected”.
A few keys never reach a web page: Fn (handled by the keyboard), some media and brightness keys, and shortcuts the operating system grabs first. On Windows, Print Screen is reported only when released.
Ghosting and rollover
Cheap keyboards share wiring between keys, so some combinations of three or more keys can't all be detected. Gaming keyboards advertise “n-key rollover” (every key at once). Hold your usual game combinations and watch the “Most keys held at once” count.
Frequently asked questions
How do I test keyboard ghosting?
Hold down several keys at the same time (for example W, A, S, D and Space). The tester shows the most keys it registered at once. If a key you're holding doesn't light up, your keyboard can't register that combination.
Why doesn't the Fn key light up?
Fn is handled inside the keyboard itself and never reaches the computer, so no website or app can detect it. Some keys, like Print Screen or the Windows key, may also be captured by the operating system.
Does it work with AZERTY or QWERTZ keyboards?
Yes. Keys are detected by their physical position, and in Chrome and Edge the labels follow your keyboard layout.