How the keyboard test works
Press every key on your keyboard. Each key the browser receives turns green; the key you're holding lights up blue. Below the keyboard you'll see the key name and its technical code.
Keys are matched by their physical position, so you can also spot a wrong keyboard layout in your OS: if pressing Y types “z”, your system is set to a German layout, for example.
Testing ghosting & n-key rollover
Hold several keys at once, e.g. W + A + Shift + Space. “Max. simultaneous” shows how many keys your keyboard detects in parallel. Cheap office keyboards often handle only 2–6 keys, while gaming keyboards with n-key rollover handle many more. Missing keys are called ghosting.
Key not working? Fixes
Key doesn't respond at all
- Try another USB port or computer to rule out a software problem.
- Mechanical keyboards: pull the keycap and blow compressed air under the switch. On hot-swap boards you can replace the switch.
- Laptops: carefully remove crumbs under the key with compressed air.
Key types twice (chattering)
If a letter appears twice when pressed once, the switch is dirty or worn. Compressed air or contact cleaner often helps. Many gaming keyboards offer a “debounce” setting in their software.
Wrong characters
If keys type different characters than printed, your keyboard layout is wrong. Windows: Win + Space switches layouts. macOS: System Settings → Keyboard → Input Sources.
Fn and media keys
The Fn key and many special keys are handled inside the keyboard and never reported to the OS or browser, so it's normal that they don't show up.