NKRO Test

Number of simultaneously pressed keys:

Current: 0
Maximum: 0

What is NKRO?

NKRO (N-Key Rollover) describes a keyboard’s ability to report all supported simultaneous key presses. It describes rollover, not input latency or polling rate.

How Do I Test NKRO?

Press several keys simultaneously.
Check whether every pressed key appears in the test.
Add more keys to find the largest combination visible to the browser.

Rollover types

2KRO: reliably reports two simultaneous non-modifier keys. Some larger combinations may work, but they are not guaranteed.
6KRO: reports up to six simultaneous non-modifier keys. The USB HID boot-keyboard report contains six key slots and a separate modifier byte.
NKRO: is designed to report all supported simultaneous keys. The result can still depend on keyboard firmware, connection mode, operating system, and software.

Why is NKRO important?

Gaming — helps prevent blocking in multi-key combinations.
Fast typing — reduces missed overlapping key presses.
Complex shortcuts — allows several modifiers and regular keys to be used together.

Browser test limitations

This page counts KeyboardEvent events delivered by the operating system and browser. System shortcuts, Fn, Touch ID, and some media keys may be handled before the page receives an event. The result therefore describes browser-visible rollover rather than a laboratory certification of the keyboard.

Sources: USB HID specification and W3C UI Events.