Keyboard Tester

What this keyboard test checks

The on-screen layout mirrors a standard full-size keyboard, including the function row, main block, navigation cluster, and arrow keys. As you press keys, each one turns blue while it is held down and stays green after it has registered at least once. That running record makes it easy to see at a glance which keys you have already confirmed and which ones you still need to try.

The counters track how many unique keys have been seen, how many are held right now, and your maximum rollover, which is the most keys the keyboard reported at the same time. The last press panel shows the raw event.key and event.code, so you can tell a physical key from the character it produces. This matters when a key sends the wrong output or your layout has been remapped.

This is a fast way to vet a new mechanical keyboard, confirm a repair, or rule out hardware before you blame a game or app. Because the test reads standard browser keyboard events, it works the same on laptops and external keyboards.

Reading your results and fixing a bad key

A healthy key flashes blue on press and turns green once, with no help from you. A dead key never lights up no matter how hard you press, which usually points to a hardware fault, debris under the keycap, or a driver problem. A stuck key stays blue after you let go, or the press history keeps repeating a character you did not intend.

If a single key fails, power down and gently clean around it with compressed air, then reseat the keycap if it is removable. If a whole row or block is dead, the issue is more likely a loose ribbon cable, a bad USB port or cable, or a driver, so try another port and reinstall the keyboard driver. On a laptop, a full shutdown and restart clears many stuck-key states before you consider service.

Keep in mind that some combinations never reach this page. Operating-system and browser shortcuts, plus a few media and function keys, can be intercepted before the browser sees them, so a missing light there does not always mean a broken key. Low-cost keyboards also limit how many keys register together, which caps the rollover number you will see.

Key codes and remapped layouts

The last press panel shows two values for a reason. The event.code is the physical location on the board, such as KeyA, while the event.key is the character that location produced, such as the letter a. When a key types the wrong character, comparing the two tells you whether the hardware is fine but the layout has been remapped in software.

This is common after switching between a US and international layout, or when a game or utility has reassigned keys. If the code is correct but the key is wrong, the fix is in your keyboard language settings rather than the hardware. If the code itself is wrong or missing, the problem is physical and belongs with the cleaning and reconnection steps above.