How to use the Keyboard Tester
- Click the on-screen keyboard so it has focus. A colored outline shows that keyboard capture is on.
- Press every key on your physical keyboard, one at a time. Each key turns blue while held and green once it has worked.
- Look for keys that never turn green (dead keys) or stay blue after you let go (stuck keys).
- Read the details panel to see the exact key, code and location your system reports. Press Esc twice to leave the tester.
Features
- Full ANSI layout with function row, navigation keys and numpad
- Live highlighting while a key is held and green once tested
- event.key, event.code, location, keyCode and modifier details
- Tested-key counter with progress bar
- Detects keys that send only keyup, like Print Screen on Windows
- Browser shortcuts such as Ctrl+W and F5 are never blocked
Common keyboard problems this tester finds
- Dead keys: a key never lights up. Dirt under the keycap, a failed switch or a broken trace is usually the cause.
- Stuck or chattering keys: a key stays highlighted after release, or one press shows as several in the history. Worn mechanical switches often chatter.
- Wrong characters: the key lights up in the wrong place or event.key shows an unexpected symbol, which usually means the operating system is set to a different keyboard layout.
- Ghosting: when you hold several keys at once, one of them does not register. Hold combinations you use in games, such as W + A + Shift + Space, and see which ones light together.
Key, code and location explained
Every key press reaches the browser with several pieces of information. event.code identifies the physical key position, such as KeyQ, regardless of language, which is why this tester uses it to light up the layout. event.key is the character or action that key produces with your current layout and modifiers, so the same physical key reports “q”, “Q” or “a” on a French AZERTY layout. Location tells left and right modifiers apart and marks numpad keys. keyCode is an older numeric value that some legacy software still uses.
| You press | event.key | event.code | Location |
|---|---|---|---|
| Left Shift | Shift | ShiftLeft | Left |
| Shift + 1 | ! | Digit1 | Standard |
| Numpad 5 (Num Lock on) | 5 | Numpad5 | Numpad |
| Space | (space) | Space | Standard |
Keys a browser cannot see
Some keys never reach web pages. The Fn key is handled inside the keyboard itself, so only the result (for example, a volume change) is visible. Media keys, brightness keys and some laptop function keys are captured by the operating system. Shortcuts such as Ctrl+W, Ctrl+T, Alt+Tab, Ctrl+Alt+Delete and Cmd+Q are handled by the browser or system before the page, and this tester intentionally lets them work normally. Print Screen on Windows only sends a key-release event; the tester counts it anyway.
Fixing common issues
- Turn the keyboard upside down and gently tap it, or use compressed air between the keys.
- For wireless keyboards, replace or charge the batteries and re-pair the receiver.
- Try another USB port, and avoid unpowered hubs.
- Check the input language and layout in your system settings if characters are wrong.
- Test the keyboard on another computer to tell hardware faults from software ones.
The tester runs entirely in your browser and does not record what you type. Phone and tablet on-screen keyboards do not report physical key codes, so use a physical keyboard. To measure your speed afterwards, take the Typing Speed Test.
Frequently asked questions
Why does a key not light up?
Either the key is not sending a signal, or the operating system intercepts it, as happens with Fn, media keys and some shortcuts. Try the key in a text editor; if nothing happens there either, it is likely a hardware fault.
Will this tester block shortcuts like Ctrl+W?
No. Combinations with Ctrl or Cmd and the F5, F11 and F12 keys are always passed to your browser. Only keys that would scroll or move focus are held back while the tester is active.
How do I leave the tester with the keyboard?
Press Esc twice quickly to release keyboard capture, or click anywhere outside the keyboard. Click the keyboard again to resume.
Can I test for ghosting or key rollover?
Yes. Hold several keys together and check that each one turns blue. If one does not, your keyboard cannot register that combination at the same time.
Is what I type recorded?
No. Key presses are only used to light up the on-screen layout and show their details. Nothing is saved or sent anywhere.