Keyboard Ghosting Test

About the Keyboard Ghosting Test

The Keyboard Ghosting Test checks the key combinations you actually use, one at a time, and tells you whether all of them reach your computer together. It is built for the moment a game ignores a jump while you are running diagonally, or a shortcut fails only when it is pressed quickly.

What ghosting is

Most keyboards do not wire each key separately. Keys sit on a grid of rows and columns, and the controller finds a press by looking for a connected row and column. When three held keys form three corners of a rectangle on that grid, the fourth corner looks pressed as well. A keyboard either reports that phantom key — true ghosting — or, far more often today, refuses to report the third key at all, which is called blocking. Keyboards with a diode on every key remove the ambiguity entirely, which is what “anti-ghosting” and n-key rollover boards pay for.

How this test reaches a verdict

• Passed — every key in the combination was down at the same moment.
• A key never arrived — at least one key did not register while the others were held. Repeat it once: if it fails again, that combination is blocked on this keyboard.
• Not held together — every key arrived, but never all at once. That is a finger timing slip, not a keyboard fault, and the test says so rather than guessing.
• Extra key — a key arrived that is not in the combination. If you did not press it, that is a ghost.

Ghosting is not rollover

The Key Rollover Test asks how many keys can register at once. This test asks whether particular keys can. Because blocking depends on where keys sit on the wiring grid, a keyboard can hold ten keys in one pattern and still drop the third key of W, A and Space. Test the combinations your game or workflow needs, not only the total.

Not every failure is the keyboard

Some combinations never reach a web page for reasons unrelated to the matrix. Operating system shortcuts such as Alt+Tab, Win+L and Cmd+Tab are taken first, and browser shortcuts such as Ctrl+W close or open tabs before a page can object — which is why none of the combinations here use Ctrl, Alt or the Windows and Command keys. If a combination fails here and works in your game, it is worth trying in a second browser before blaming the hardware.

What stays on your device

Nothing is sent anywhere. The summary download lists each combination and its result, and nothing about what else you typed.

Related checks

• Keyboard Test — whether each key registers at all.
• Key Rollover Test — how many keys register at once.
• Key Chatter Test — one press registering twice.

Where this tool stops

The combinations are fixed so that results can be compared between keyboards. Laptop keyboards and some wireless boards use their own firmware rules, so a combination that fails can still be a limit of that design rather than a defect. Only keys that reach the browser can be checked.