N-Key Rollover Test Page

Use this page to test your keyboards N-Key Rollover


Using This Demonstration
Click on the keyboard shown below. It will then show what keys are being pressed on your keyboard (or to be more specific, the ones that are being passed to your web browser). You can use this to see if there are certain key combinations that fail to work correctly.




If you prefer a more fool proof method of testing your N-Key Rollover, AquaKeyTest is a Windows based program that installs locally and listens to the output your keyboard is actually sending to the computer. This program can also be used to test every key on your keyboard, and is not faked out by scripts or any hotkey shortcuts or macros that may be on the keyboard.


How To Hunt For Ghosts
Ghosts can be somewhat elusive. Just because you find some combination of 6 keys that reports correctly does not necessarily mean that every combination of 6 works. In fact, the most straightforward keyboard design has thousands of 3-key combinations that do not work! That is a lot, but it is still less than 5% of the total number of 3-key combinations.
A quick way to find problematic combinations is to press and hold ASDW (the most popular keys for moving around in games), and then while holding those down, press every other key in turn. If you find a key that does not work, try releasing some of the ASDW keys. Odds are high that you will find a 3-key combination that fails.


  • Peter says:

    I love this little test. It's great watching keypresses in real time. But, I'm not sure about the N-key Rollover.

    I am using a Filco Tenkeyless MX Black mechanical keyboard. I came with USB as standard and the purple PS/2 adapter to plug into the 'legacy' PS/2 port on the mobo.

    I wasn't happy with that so I modded it out to a dedicated PS/2 connection on the mobo instead of PS/2 by adapter.

    I feel it works better. More direct some how. I can't really explain the difference but it feels more snappy it that makes sense.

    Just my two bits.

    Also, is that your own keyboard demo? It's pretty nifty. It's just that I type in Colemak, so whilst the keys are they same, they are 'displayed' as QWERTY. I was just wondering if you could adapt the code to reflect a Colemak etc layout?


  • G.G. Campbell says:

    Very slick.
    Any chance of seeing the source and how you did this?
    I wanted to capture the n-key rollover stuff in javascript.

  • Cawston says:

    so i have a six key rollover for typing and a setting for gaming that allows me to hold down every key at once what is the advantage to having a six key rollover compare to the n key function why not just default to the nkey and leave the button out?

    • Cawston: 6-key is a limitation of the USB human-interface-device standard. A lot of gaming keyboards can understand n keys, but can only send up to 6 when connected via USB unless using a non-standard protocol requiring a driver specific to that keyboard.

      • DOGMA1138 says:

        Not true, most high end modern keyboards bypass the limitation without needed an additional driver. They'll use 1/2 USB connection, and register multiple HID devices at the same time to give key roll over greater than 6, most of them can do N-Key roll over over USB now quite reliably.

  • sdafasd says:

    I was skeptical when I read that my tt posidion keyboard supported n-key rollover via usb since I had read about the 6 key limitation. I run windows 7 and I never installed any drivers, and I don't think any came with the keyboard, but it shows all key presses even when I palm the keyboard. anyone care to explain? I came here just to test that claim after i tested with notepad.

  • Namontack says:

    razer blackwidow does not allow more than two arrow keys to be pressed. what a let down -_- do NOT buy razer products, they're cheaply made, buggy and unreliable. at this point, im not sure which brand to go with. my logitech k320 has unlimited rollover (EVERYTHING PRESSES at the same time). I just don't like that its membrane and sometimes sticks.

    • Aman says:

      Not true I have razer blackwidow tournament edition. Even without downloading Razer Synapse all arrow keys can be pressed down at the same time

  • peteer01 says:

    I love my PS2 mechanical keyboard with Cherry MX Black switches. I understand that things are getting better with USB keyboards, but PS2 just works.

  • […] can use this website to test your keyboard – click on the embedded flash app and press several keys […]

Leave a Reply

XHTML: You can use these tags:
<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>

%d bloggers like this: