Keyboard Tester — Check Every Key

Press a key and it lights up on the on-screen layout. Tested keys stay coloured, so it's easy to see which keys you haven't tried and which ones never respond at all. Hold several keys at once to find your keyboard's simultaneous-input (NKRO) limit.

How to use

Press any key. It lights up and stays marked as tested.
If a key never responds, that key is dead — check the "not tested yet" list below to see what's missing.
Hold several keys together and watch how high the "most at once" number climbs.

FAQ

The Windows key and Cmd+Tab don't register.

The operating system takes those before the browser ever sees them. A web page can't intercept them, so those keys can't be tested here.

Simultaneous input stops at 6. Is my keyboard broken?

No. Ordinary USB keyboards are specified to report at most six keys at once (6KRO). Going beyond that needs a keyboard that supports NKRO.

I press a key and a different character appears.

The layout shows the physical key position (the browser's key code), independent of your input method or layout. Pressing Q on a non-QWERTY layout still lights the Q position, and that's correct.

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