Keyboard tester

How to test every key

1. Click the keyboard above so it says it is listening. On a desktop it starts listening on its own.
2. Press each key once. Keys turn green with a tick when the browser has received them.
3. Look at the counter. It counts the keys of the layout you picked, for example 104 for a full-size board.
4. Press Reset to start again, or Copy results to paste a summary into a message to a seller or support team.

Pick the layout that matches your board: full size, TKL (no number pad), 75% or 60%. The layout only changes which keys are drawn and counted. The browser reports the same key codes either way.

Held, tested and untested keys

A key held down right now is amber with a thick outline and sits slightly lower. A key that has been pressed at least once is green and carries a tick, so the state is clear without relying on colour alone. Keys not yet pressed stay dark. The panel next to the board shows the last key, its code (the physical key), its key (what it types) and the legacy keyCode number.

The Windows and Mac label switch only changes the printed names, for example Win and Cmd. Keys outside the drawn layout, such as an extra key on an international board, appear under "Other keys seen".

Keys the browser cannot see

A web page only receives what the operating system passes on. These are normally invisible here, and it is not a fault in your keyboard:

• Fn. On most laptops and compact boards Fn is handled inside the keyboard and never reaches the computer as its own key.
• Media, brightness and volume keys. Many are taken by the system first. Some browsers report them as extra keys, many do not.
• Win and Cmd combinations. Shortcuts such as Win+L, Cmd+Tab or Ctrl+Alt+Delete are handled by the system before the page.
• PrintScreen. On some systems it triggers a screenshot and the browser sees only the key release, or nothing.

While the tester is listening it blocks the page from scrolling or navigating on Space, the arrow keys, Backspace, Tab and the F keys. Press Ctrl or Cmd with a key to use browser shortcuts as normal. Click outside the board, or press Stop listening, to hand the keyboard back.

Rollover and chatter

The Rollover check counts how many keys are down at the same moment and remembers the highest number. If you hold six keys and the tester reports four, the board, its cable or the system dropped two. The full explanation is on the keyboard ghosting test page.

Key chatter is one press that registers twice. The tester flags a key that goes down twice less than 30 milliseconds apart; a human finger cannot do that on purpose. Auto-repeat from holding a key is ignored.

A key does not light up: what to try

First press it a few times, harder and at its edge, since a worn contact sometimes works only in one spot. Try another USB port or the cable. On a wireless board, replace the battery and move the receiver closer. On a laptop, check whether the key needs Fn. If the key still never appears here but other keys do, test the board on a second computer: a key that is dead everywhere has a hardware fault, while a key that works elsewhere points to software, such as a remapping tool.