Keyboard Tester
Check which keys register, and how many at once
Keyboard
Keys the browser reserves, such as F5 and F12, may not register here.
A key that occasionally does nothing is hard to prove and easy to doubt. Press every key here and watch which ones light up — and hold several at once to see how many your keyboard can report together.
How to use
- 1 Click the page once so it receives keystrokes.
- 2 Press each key and watch it highlight.
- 3 Keys you have tested stay marked, so you can work through the whole board.
- 4 Hold several keys at once to check simultaneous input.
Frequently asked questions
Why do some keys not register?
The browser reserves a few. F5 reloads, F12 opens developer tools, and the OS may claim volume and brightness keys before the page ever sees them. Those are not faults.
What is key rollover?
How many keys a keyboard can report simultaneously. Cheap membrane keyboards manage two or three before extra presses are dropped; gaming keyboards advertise n-key rollover, meaning no practical limit. It matters for games, not for typing.
What is the difference between code and keyCode?
"code" is the physical position on the board and does not change with the layout. keyCode is the deprecated numeric legacy value. If you are writing code, use "code" or "key" — never keyCode.