Keyboard Tester
Check every key on your keyboard, including the ones the OS normally swallows.
Dashed keys are reserved by the operating system or the browser and normally never reach a web page. Leaving them grey is expected and is not counted against your keyboard.
How this test works
Press "Start listening" and then work across the keyboard. Each key lights blue while it is held and green once it has registered, and the test identifies keys by their physical position rather than the character they produce — so the key to the left of "1" registers whether it prints a backtick, a superscript two or a less-than sign. A key that sends a press but never sends a release is reported as stuck, which is the fault worth acting on. About a dozen keys are drawn with a dashed outline: those are claimed by the browser or the operating system and never reach a web page, so leaving them grey is expected and is not counted against your keyboard.
What the results mean
- Keys registered
- Distinct physical keys that produced a key-down event. Work along each row so nothing is left grey simply because you did not press it.
- Reserved, untested
- Keys the browser or the OS takes first — fullscreen, developer tools, the screenshot key, the Windows or Command key and the menu key. They are excluded from the count because a web page cannot see them even on a perfect keyboard.
- Stuck keys
- A key that sent a press and never sent a release. That is either something physically jamming the key or a failed switch, and it is what causes a character to repeat endlessly.
- Extra keys seen
- Media and macro keys outside the standard layout. Seeing them is a bonus, not a requirement.
Common problems and fixes
- A key on my keyboard never lights up here
- Check whether it is drawn with a dashed outline first — those never reach a web page. If it is a normal key, try it in a text editor: if nothing types there either, the key or its switch has failed.
- The Fn key does nothing on this page
- Fn is handled inside the keyboard controller and never becomes a browser event on any keyboard. The keys it modifies — brightness, volume, media — often do not either. This is expected and not a fault.
- The letters light up in the wrong places
- The drawing is a US ANSI layout. On AZERTY, QWERTZ or an ISO board the physical positions are correct but the printed characters differ, so the highlighted key is the right one even when the letter looks wrong.
- One key types two or three characters at a time
- That is switch chatter, the keyboard equivalent of a double-clicking mouse. A clean and reseat sometimes helps on a mechanical board; on a membrane keyboard it usually means replacement.
Frequently asked questions
Why do some keys not register on this keyboard tester?
Because the browser never receives them. F11 is fullscreen, F12 opens developer tools, PrintScreen belongs to the operating system screenshot tool, and the Windows or Command key opens the launcher — the OS or the browser consumes each one before the page is told anything. The Fn key is different again: it is resolved inside the keyboard controller, so no computer ever sees it as a key press. Those keys are drawn dashed here and left out of the score, because reporting them as dead is how other testers convince people to replace a working keyboard.
How do I know if a key is actually broken?
Press it in a plain text editor. If nothing types and nothing lights up here, and it is not one of the reserved keys, the key or its switch is at fault. Before replacing anything, try the keyboard on a second machine — a key that works there points at a driver or a layout setting on the first one rather than hardware.
What causes a key to get stuck?
Most often something physical: a crumb, dust or dried liquid under the keycap holding the switch closed. Turn the keyboard upside down and shake it firmly, then pop the keycap and clean around the switch. A stuck key that survives a clean is usually a failed switch, and on a membrane keyboard that means the board rather than the key.
Does this work for a laptop keyboard?
Yes, with one caveat: laptops have no numeric keypad and their function-row keys are frequently media controls that need Fn to reach F1–F12. The main block is what matters, and it tests identically.