Keyboard Ghosting Test
To test for ghosting, hold all keys of a combination at once, such as W, A, Shift and Space. If every key lights up, the combination works. If a key you are holding stays dark, the keyboard is blocking it. If a key you are not touching lights up, that is a ghost key.
Ghosting test
You need a physical keyboard for this test. On a phone or tablet, connect a keyboard by Bluetooth or USB first. The on-screen keyboard of a phone does not report which physical key you pressed.
Click here first, so the page receives your key presses.
The page lost focus, perhaps because of Alt+Tab, the Windows key or a shortcut. Click anywhere on the page and continue.
Hold all keys in a row at the same time. A row turns green when every key in it arrived together.
- Held now
- Worked
- Suspected double press
- Held 2 s or longer
- Not pressed yet
- Usually invisible to browsers
Last keys
Keys that are not on this picture
How it works
Press keys on your keyboard. Each key lights up on the picture while you hold it and stays teal once it has worked. The page reads the key events your browser already gives every web page and never sends them anywhere.
This test needs JavaScript. The explanations below work without it.
How to do it
- Click once on the page.
- Hold all keys of the first row at the same time.
- Check that every key in the row turns green, and that no other key lights up.
- Repeat for the other rows and for combinations you use.
Blocking and ghosting
Inside most simple keyboards, keys share wires in a grid. When certain keys are held together, the keyboard cannot tell exactly which ones are down. Most keyboards then block the extra key: you press it but nothing happens. On some keyboards a key you did not press shows up: a ghost key.
Keyboards with a diode for every key, common on mechanical and gaming models, avoid both problems. The combinations that fail are different from one keyboard model to the next, so test the ones you use.
Try your own combinations
The rows above are common in games and shortcuts. You can hold any keys you like: the on-screen keyboard shows every key the browser receives. A held key that stays grey is blocked.
Frequently asked questions
What is keyboard ghosting?
Ghosting is when a keyboard reports a key you did not press, because several held keys share wires inside it. More common is blocking, where an extra key you press is not reported at all. Both happen only when several keys are held at once.
How do I know if my keyboard has ghosting?
Hold the combinations you use, for example in your favourite game. If any key you hold stays dark, or a key you do not touch lights up, the keyboard cannot handle that combination.
Can software fix ghosting?
No. It comes from how the keyboard is built. Some keyboards have a gaming mode that changes how keys are reported, but if a combination is blocked by the hardware, only another keyboard helps.
Last updated: November 2, 2026