How to test N-key rollover on a gaming keyboard

You hold down several keys in a game, but one of your movements or actions does not register. The keyboard may have a rollover limit, or the problem may be in the game, the keyboard connection, or a setting.

Use the Keyboard Test to check which keys register together. You can compare everyday gaming combinations with larger groups of keys, then find out whether the limit follows the keyboard or appears only in one game.

Test N-key rollover

1. Open the Keyboard Test on the computer connected to the gaming keyboard. Make sure the browser page can receive keyboard input.
2. Press and release a few keys one at a time, such as W, A, S, D, Space and Shift. Check that each one registers on its own.
3. Hold down a familiar gaming combination, such as W + Shift + Space, and add keys one at a time. Watch which keys the test recognizes while you hold them together.
4. Release all the keys, then try a different combination with the same number of keys. Some keyboards have limits that depend on which keys you press together, so test the combinations you actually use.
5. Try the same combinations in the game. If every key registers in the browser but not in the game, check the game’s controls and input settings before blaming the keyboard.

Keep each test brief and release all keys between combinations. Do not use Fn, the Windows key or Print Screen to judge rollover. Those keys, along with many laptop shortcut keys, may be handled by the operating system before the browser can detect them.

What the result means

All the keys register together

The keyboard handles that particular combination. This does not prove that every possible combination will work, so test your usual movement and action keys as well as a few larger groups. “N-key rollover” means a keyboard can register multiple simultaneous key presses, but the name alone does not guarantee that every key combination behaves identically.

Some keys stop registering as you add more

The keyboard may have a rollover limit for that combination. A common limit is six simultaneous key presses, sometimes called 6-key rollover, but some keyboards have different limits or combinations that work better than others. Try another group with the same number of keys. If it works, the limit may depend on the keyboard’s key layout or operating mode.

An extra key registers even though you did not press it

This is called ghosting: the keyboard reports a key that was not pressed. If keys simply stop registering without extra keys appearing, that is usually described as key blocking. Both can result from the keyboard’s key matrix, the circuit layout used to read its keys.

Every key works in the test, but not in one game

The keyboard is probably registering the presses correctly. The game may use different controls, ignore a particular input combination, or have a setting or profile that changes how the keys behave. Check the game’s key bindings and compare with another game before changing keyboard hardware.

How to fix it

1. Check that the test has keyboard focus. Click the test page if needed, then try again. Make sure the browser is not focused on the address bar or another text field. Browser and operating system shortcuts can also take certain keys before the test receives them.
2. Test the exact keys that fail. Try your usual game combination, then test those keys in smaller groups. If one key fails even when pressed alone, the issue is not just rollover. For an intermittent key, see how to find a key that sometimes stops working.
3. Check accessibility keyboard settings. On Windows 11, open Settings › Accessibility › Keyboard and check whether Sticky Keys or Filter Keys is changing how presses are handled. On macOS, open System Settings › Accessibility › Keyboard and check Sticky Keys and Slow Keys. These settings affect how key presses are interpreted, so turn them off temporarily if you do not use them.
4. Check the keyboard’s mode and profile. Some gaming keyboards offer a setting for 6-key rollover or full N-key rollover, and a software profile may change the behavior. Check the keyboard’s manual or its control software for the correct mode. Do not try an unfamiliar key combination from a different model, because shortcuts vary by keyboard.
5. Reconnect the keyboard. If it is wired, connect it directly to another USB port instead of a hub. If it is wireless, check the battery and receiver connection. Then repeat the same test.
6. Compare it on another computer. Test the same combinations on a second computer if possible. This helps separate a keyboard limitation or fault from an operating system setting, browser issue or game configuration.

When it is a hardware problem

If a key does not register on its own, or the same unwanted keys appear across different computers, the issue may be a damaged switch, a keyboard circuit fault or a failing connection. A keyboard that only blocks certain combinations may be working as designed, rather than broken. Check the product specifications for its rollover support and return or warranty options. If individual keys fail across computers and the keyboard is out of warranty, replacement is often more practical than repair.

What a browser test can and cannot check

The test checks the key events that reach the browser. It cannot see keys that the operating system intercepts, and it does not identify the keyboard’s internal circuit design or prove that every combination will work in every game. Laptop Fn keys and many system shortcuts are usually handled before a web page can receive them. For a useful comparison, focus on regular keys that the browser can detect, and use the same combination in the game where you noticed the problem.