Understanding N-Key Rollover (NKRO)
If you've ever pressed multiple keys simultaneously and heard your computer make a "beep" sound—or noticed that some of your actions didn't register—you've encountered a rollover limit. In the world of high-performance computing, N-Key Rollover (NKRO) is the ultimate solution.
In mathematics, "n" represents an unlimited number. A keyboard with NKRO can register as many keys as you can physically press at the exact same time. This is the opposite of a standard 2-key or 6-key rollover board.
The Evolution: From 2-KRO to NKRO
Early office keyboards often had 2-KRO, meaning if you held 'A' and 'S', the third key might be ignored. Most modern USB keyboards default to 6-KRO due to the limitations of the standard USB HID (Human Interface Device) protocol. To achieve true NKRO, manufacturers use a more complex internal circuit matrix where every single switch has its own diode. According to technical hardware standards, this prevents current from flowing backward and causing "ghosting."
Why NKRO Matters for Gamers
For casual typing, 6-KRO is more than enough—you rarely press more than six keys at once while performing a keyboard typing test. However, in genres like fighting games, rhythm games, or complex FPS titles, you might need to hold down three movement keys, a sprint key, and an action key simultaneously. Without NKRO, your keyboard test would show missed inputs, leading to a loss in competitive play.
Test Your Rollover Limit
How many keys can your board handle? Use our online keyboard test to find out. Mash your keys and watch the "Unique Hits" counter.
Launch Keyboard TestHow to Test NKRO Online
You don't need expensive software to check your rollover. Simply open an online keyboard test and press as many keys as possible using both hands. If the on-screen display stops adding new green highlights after 6 keys, your board is likely limited by its USB controller. If it lights up 10, 20, or more, you have a high-performance NKRO device.
Conclusion
While NKRO isn't necessary for everyone, it is a hallmark of quality in mechanical keyboards. Whether you are aiming for a high score in a keyboard typing test or a victory in an esports tournament, having a board that never "forgets" a keystroke is a massive advantage.