How to use it
- Click this page once so it has focus, then press any key.
- Press every key: each one turns green when the computer receives it, and stays highlighted while you hold it.
- Hold several keys together to see how many register at once (ghosting test).
Questions and answers
How do I know if a key is broken?
If you press a key and it does not light up on the map, the computer is not receiving it. Try it again in another program; if it still fails, the key or its switch needs cleaning or repair.
Why doesn’t the Fn key light up?
Fn is handled inside the keyboard and is never sent to the computer, so no website can detect it. Media keys and some laptop keys work the same way.
What is ghosting or key rollover?
It is how many keys a keyboard registers at the same time. Hold several keys and watch “Held now”: many office keyboards stop at 3 to 6 keys, while gaming keyboards often register all of them.
Does it work with laptop and Mac keyboards?
Yes, with any keyboard connected to a computer, including laptop, Mac, wireless and Bluetooth keyboards. A few keys such as PrtSc or ⌘ may be taken by the system before the browser sees them.