Online Keyboard Test
Test individual keyboard keys online, see stuck or missing key events, simultaneous presses, rollover, possible ghosting, and suspected double input locally in your browser.
Start keyboard test
Tested keys: 0 / 66
Pressed now: 0
Maximum registered together: 0
Last key
Press a key to see its value and physical code.
Held keys
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No possible double input detected
Hold several keys together. If a physically held key does not light up, that combination may be limited by rollover, ghosting, or the input system.
For a full check, connect a physical keyboard.
Key presses are processed locally in your browser and are not stored.
Browser test limitations
- The operating system may intercept shortcuts such as Ctrl+Alt+Delete, Cmd+Tab, or Win+L.
- Fn is often handled by keyboard firmware and may not reach the browser.
- The test shows only events delivered to this page; browser and device behavior varies.
How to test your keyboard
Start the test, then press each key once and check that its physical key lights up. Hold several keys together to see the events the browser receives, then repeat any result that seems unusual.
How to check a key that isn't working
If a key never appears, try it several times, in another browser or application, and with another keyboard layout. For an external keyboard, also check the cable, receiver, Bluetooth connection, or port before drawing a conclusion.
Keyboard ghosting and rollover
Rollover describes how many simultaneous key events a keyboard reports. Ghosting or blocking can make a particular combination unavailable. This page can show received events, but it cannot see a physical press that the operating system never sends to the browser.
Stuck keys and double typing
A key remains shown as pressed until a keyup event arrives; changing windows clears this state to avoid a false stuck-key warning. A rapid release and second independent press is only a possible double-input signal: normal repeat events and one observation do not prove a hardware fault.
Frequently asked questions
How do I test a keyboard key?
Start the test and press the key. Its matching physical key is marked when the browser receives the event.
What is keyboard ghosting?
It is a limitation where some simultaneous key combinations are blocked or produce unexpected input. This test can only show events that arrive.
What is N-key rollover?
It describes a keyboard's ability to register many keys together. The maximum shown here is what you demonstrated in this session, not a hardware rating.
Why doesn't the Fn key appear?
Fn is commonly processed by the keyboard or firmware before the operating system and browser can receive it.
How can I check for double typing?
Repeat a suspected key. The tool marks very fast independent presses as possible double input, while ignoring normal held-key repeat events.