Keyboard Tester
Press every key and watch it light up โ find dead or sticky keys.
About this keyboard tester
Press keys and watch them light on the on-screen board. A key that lights is reaching the operating system; one that never lights is genuinely dead, not just misbehaving in one application. Keys stay green once seen, and the counter tracks coverage โ a full sweep of the board takes under a minute.
The readout also shows each event's code and key values, which is
what web developers come here for when naming keyboard shortcuts.
Diagnosing what you find
A dead key on a desktop keyboard is usually debris under the switch โ a blast of compressed air fixes more keyboards than any other repair. On a laptop, a cluster of dead keys often means the ribbon cable, and a single one a failed dome or switch.
A key that fires twice per press (chattering) is a worn switch. A key that types by itself is stuck โ worth checking before blaming malware. And if several keys pressed together drop one, that is ghosting, a limitation of the keyboard's wiring matrix rather than a fault; cheaper boards handle fewer simultaneous keys, which is why gaming keyboards advertise N-key rollover.
Media keys and the Fn row often never reach the browser because the keyboard's own firmware handles them โ that is normal. Test the mouse next if the desk is being audited: the mouse tester covers buttons, wheel and double-click.
Frequently asked questions
How do I test if my keyboard keys work?
Open this page and press each key. Keys that reach the operating system light up and stay green; any key that never lights is faulty at the hardware level, not just in one app.
Why do my media and Fn keys not show?
Many keyboards handle those in firmware and never send them to the computer as ordinary key events, so the browser cannot see them. It is normal, not a fault.
What is keyboard ghosting?
When several keys held together cause an extra or missing keypress. It comes from the keyboard's wiring matrix; try pressing three-key combinations here to see how yours copes.
A key types double letters โ is that fixable?
That is switch chatter, common on ageing mechanical switches. Cleaning sometimes helps; otherwise the switch (or on hot-swap boards, just that switch) needs replacing.
Does this work with any layout?
Yes. The tester lights physical key positions, so AZERTY, QWERTZ and other layouts light the same keys โ the readout shows both the physical code and the character your layout produced.