Keyboard test
Press any key and it lights up below. Hold several at once to see how many your keyboard can register simultaneously — the limit that decides whether a game misses your inputs.
Click here first, then press keys. Keys stay highlighted once pressed so you can work across the whole board.
- Held now
- 0
- Most at once
- 0
- Keys seen
- 0
- Last key
- —
Rollover and ghosting
Cheaper keyboards share wiring between keys, so pressing certain combinations produces a key you never touched, or drops one you did. That is ghosting, and it is why a keyboard can feel fine for typing and fail during a game.
Hold down four or five keys across different parts of the board and watch the counter. Anything registering six simultaneous keys plus modifiers is fine for almost everything; full n-key rollover registers every key at once.
A key that repeats or sticks
A key firing twice from one press usually means a worn or dirty switch rather than a software fault, and on a membrane keyboard it tends to get worse. A key that registers only when struck hard is the same problem earlier in its life.
Nothing here leaves your device
Every one of these tests runs entirely in your browser using standard web APIs. No audio, video, keystroke or controller input is uploaded, recorded on a server, or stored anywhere — there is no upload endpoint for any of it to go to. Closing the tab discards everything.
Common questions
How do I test if a key is broken?
Press it and see whether it lights up here. If it never registers, the switch or its connection has failed. If it registers twice from one press, the switch is worn or dirty.
What is n-key rollover?
The number of keys a keyboard can register at the same time. Many report six plus modifiers; full n-key rollover means every key can be pressed at once and all of them are read correctly.