ZZTool
What is a keyboard test?
A keyboard test is an online tool that shows whether each key on your keyboard works properly. When you press a key, the matching key on the virtual keyboard lights up instantly, together with its key name, code, keyCode and location. You can go through every key to find dead or stuck keys, and hold several keys at the same time to check anti-ghosting and NKRO (n-key rollover). Everything runs locally in your browser, and nothing you type is recorded or uploaded.
Features
Each key lights up on the virtual keyboard the moment you press it
See key, code, keyCode and location for every keystroke
Hold several keys together to check NKRO and anti-ghosting
Track which keys you have already tested and which are left
Tips
- ✓Click the keyboard area first, otherwise keystrokes are not captured.
- ✓Press several keys at once to see how many your keyboard can register (NKRO).
- ✓If a key does not light up, try another USB port or another device to rule out a connection issue.
- ✓Use Reset All to clear every result and start a fresh test.
FAQ
Why does my key not light up?
The key may be broken, blocked by debris, or disabled by software. Try it on another computer or with a different keyboard to confirm whether the problem is the hardware.
What is key rollover (NKRO)?
Rollover is the number of keys a keyboard can register while pressed at the same time. Hold several keys together and the "Max Simultaneous" value shows how many your keyboard detected.
Is this keyboard test free and private?
Yes. The test is completely free and runs entirely in your browser. No keystrokes or personal data are sent to any server.
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