Keyboard Test
Instant browser-based keyboard diagnostics. Test key rollover (NKRO), identify stuck switches, and detect switch chattering in real time.
60% · 80% · 100%Multi-Key RolloverSwitch Chatter Engine100% Client-Side
Keys Pressed0.0%
0/ 86 keys
Max Rollover (NKRO)NKRO Ready
0held simultaneously
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Last KeyChatter Alert (< 30ms)
None
Code: --
Scroll horizontally to test all keys
Tap or TypeTested: 0·Held: 0
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100% Keyboard Tested!
All keys responded with zero dead switches or missed inputs.
Fn Key Note: The physical Fn key is handled internally by your keyboard (to toggle volume, backlight, etc.) and doesn't send a signal to the computer. It is not required for 100% test completion, but you can click it on screen to test it.
Frequently Asked Questions
How does this online keyboard tester work?
This tool intercepts hardware keyboard events directly in your browser using the modern W3C KeyboardEvent API. It listens for physical scan codes (e.code) and virtual keys (e.key) to verify working keys, measure simultaneous rollover, and detect switch chatter without any software installation.
What is N-Key Rollover (NKRO) versus 6KRO?
N-Key Rollover (NKRO) means your keyboard can register every single key pressed at the exact same moment with zero missed inputs or ghosting. Standard office keyboards often support only 2KRO or 6KRO (maximum 2 to 6 simultaneous keys), while gaming and mechanical keyboards feature full NKRO over USB.
What is keyboard switch chattering (key bounce)?
Switch chatter occurs when a mechanical switch contact bounces or malfunctions, causing a single keystroke to register twice or more within milliseconds (typically < 30ms). Our diagnostic engine measures intervals between key presses and alerts you if switch chatter is detected.
Why don't special Fn or hardware volume keys register?
The Fn (Function) key and certain proprietary OEM keys (like manufacturer backlight toggles) are handled internally by your laptop or keyboard microcontroller and never sent to the operating system or browser via standard USB HID reports.
How do I fix double-typing or unresponsive mechanical keyboard keys?
Common fixes include removing the keycap and blowing compressed air into the switch housing, applying electronic contact cleaner (DeoxIT), adjusting your keyboard's debounce software filter, or replacing the hotswappable switch.