Keyboard Tester
Press keys and see each one light up to find dead or stuck keys. Your work stays on this device whenever possible.
How to use Keyboard Tester
- Click inside the test box so it receives key presses.
- Press every key; each one turns green once it has registered at least once.
- Hold several keys together and read "Most keys held at once" to check rollover.
- Watch "Keys not on the map" for media keys and numpad keys the diagram does not show.
- Press Reset to start a fresh pass, for example after cleaning the keyboard.
Worked example
Click the box and hold W, A and Shift together, then press Space. "Most keys held at once" reads 4 and all four keys stay dark while held. If Space does not light up while the others are held, the keyboard has a ghosting limit for that combination.
When to use this tool
- Checking a second-hand or new keyboard for dead keys.
- Testing whether a gaming keyboard handles the key combinations you use.
Important limitations
Keys reserved by the operating system or browser (for example the Windows key menu, Print Screen and Fn) may never reach a web page and cannot be tested here.
Frequently asked questions
How do I find a dead key?
Press every key once and look for keys that stay white. A key that lights only when pressed hard, or only sometimes, usually has dirt under it or a worn switch.
What is key rollover or ghosting?
Rollover is how many keys a keyboard can report at the same time. Cheaper keyboards often stop at 2 or 3 in some combinations, which is called ghosting. Hold keys you use together in games and check the Most keys held at once number.
My keyboard is not a US layout. Does it still work?
Yes. The tester uses each key's physical position (event.code), so it works on UK, German or French keyboards. The labels on the diagram follow the US layout, while the Last key box shows the character your layout produces.
Why don't some keys show?
The browser or operating system keeps a few keys for itself, such as the Windows key menu, Print Screen or Fn. Those may never reach a web page, so they cannot be tested here.
Is what I type recorded?
No. The page only lights keys and shows the last key pressed. Nothing is saved or sent, so it is safe to test even on a work computer.