GearCheckHow to use the keyboard tester
- Press each key once. It flashes blue while held and stays green after.
- Look for grey keys — any key that stays grey after you pressed it isn't registering.
- Test combinations you use in games, like W + A + Shift + Space, and watch Most keys at once.
- Watch for red outlines, which mark keys that registered twice from one press (chatter).
On a Mac? Use the Mac keyboard test, which shows Command, Option and the Mac layout.
Rollover and ghosting explained
Keyboards detect keys through a grid of wires. Cheaper keyboards share wires between keys, so pressing certain combinations together makes other keys appear pressed (ghosting) — to prevent that, the keyboard blocks extra keys. This is called key rollover:
| Rollover | Meaning | Typical keyboards |
|---|---|---|
| 2KRO | Only two keys at once are guaranteed | Old or very cheap keyboards |
| 6KRO | Six keys plus modifiers | Standard USB keyboards |
| NKRO | Every key at once | Most gaming and mechanical keyboards |
If your result is lower than expected, try different combinations — rollover can vary across the keyboard — and check whether your keyboard has an NKRO mode in its software or a key combination to enable it.
A key isn't working — what to try
- Only in one app? If the key lights up here, the keyboard is fine; check that app's key bindings.
- Dirt or crumbs: turn the keyboard upside down and tap it, or use compressed air at an angle under the keycap.
- Wireless keyboards: replace or charge the battery and move the receiver closer — weak signal drops keys.
- Several neighboring keys dead: usually a damaged ribbon cable or liquid damage on laptops; this needs repair.
- Settings: Windows Filter Keys and Sticky Keys change how keys behave. Turn them off under Accessibility → Keyboard.
Key codes for developers
The details panel shows event.key (the character produced), event.code (the physical
key), the legacy keyCode and the key location (left, right or numpad). Use it to check what your
browser actually receives when building keyboard shortcuts.
More input tests
Test your mouse buttons and scroll wheel, your game controller, or see how fast you can click with the CPS test.
Frequently asked questions
How do I test my keyboard?
Just start pressing keys. Each key lights up blue while it is held and stays green once it has worked. When every key on your keyboard is green, it is fully working. Keys that stay grey either were not pressed or are not registering.
What is keyboard ghosting and how do I test it?
Ghosting is when some key combinations don’t register because the keyboard can’t detect that many keys at once. Hold several keys together — for example W, A, Shift and Space — and watch “Most keys at once”. Basic office keyboards often manage 2–6 keys; gaming keyboards with N-key rollover register all of them.
What is key chatter?
Chatter is when one press registers as two or more, usually because a worn mechanical switch bounces. The test flags any key that goes down again within 30 ms of being released and outlines it in red. Blowing out dust can help; persistent chatter usually means replacing the switch.
Why don’t some keys light up?
A few keys never reach the browser. Fn is handled inside the keyboard itself, and the operating system reserves some combinations (like the Windows key alone, Print Screen on some systems or media keys). Those keys may not light up even when they work.
Does it work with non-English keyboards?
Yes. Keys are matched by their physical position, not the character they type, so AZERTY, QWERTZ and other layouts work. The label on screen shows the US position; the key log shows the actual character your layout produces.
Can I test a laptop keyboard?
Yes. Laptop keyboards usually have no number pad, so ignore those keys. Many laptop function keys send media or brightness commands by default; hold Fn while pressing them to test F1–F12.