N-Key Rollover Test

NKRO usually means a keyboard claims to report every key independently. This test shows how many keys the browser currently detects so you can compare with that claim.

Mobile note: N-key rollover checking needs a physical keyboard.
N-Key Rollover Check
Ready

Detected state

Browser view
Current held 0
Maximum held 0
Held keys None

Limitations: this panel reports keyboard events delivered by the operating system to this browser tab. It cannot measure hardware matrix behavior, firmware promises, USB polling, or true physical latency.

About this test

What NKRO claims mean

A true NKRO keyboard is designed to avoid matrix limits. Firmware and OS handling still affect what a browser test sees.

Build a broad chord

Hold letters across both hands, add digits, then add modifiers. Each step shows whether the detected count stays equal to the number of keys you hold.

Treat the result as evidence

A high detected count is consistent with NKRO, but a browser test cannot certify hardware. Use it as one signal among several.

Can I prove my keyboard is NKRO in a browser?

No. The browser can only report the key events the OS delivers. That is useful evidence but not a hardware certification.

Why does USB polling matter?

USB report rate limits how often key states are sent. A fast chord can briefly exceed the report rate even on capable hardware.