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Keyboard Ghosting Test & NKRO Test

Hold keys together and watch which ones the keyboard reports. You get your real key rollover, a pass or block for eight common game combinations, and a ghost hunt around W A S D.

Updated · 2 sources

Click the keyboard, then hold keys down together. Avoid Ctrl + W, Ctrl + T and the Windows key — the browser or system takes those before the page can stop them.

Click here to start

Held now
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Most at once
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…of them normal keys
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Rollover
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1 · Rollover — how many keys at once?

Lay one hand flat across the letters and press down, or hold the eight home-row keys below. Modifiers (Shift, Ctrl, Alt) are counted separately because a standard USB keyboard report carries them apart from its six key slots.

2 · Game combos — hold every key in a card at the same time

Sprint diagonal

WAShift

Not tried

Jump diagonal

WDSpace

Not tried

Sprint, strafe, jump

WAShiftSpace

Not tried

All movement keys

WASD

Not tried

Crouch-walk and reload

WDControlR

Not tried

Ability keys

QWER

Not tried

Lower-left cluster

ShiftZXC

Not tried

Eight home-row keys

ASDFJKL;

Not tried

3 · Ghost hunt

Hold W, A, S and D, and while holding them press every other key in turn. Keys that register with WASD held turn green on the picture; a key that stays grey while held is blocked by that combination.

Hold W A S D to start the hunt0 keys checked

Short answer

Hold several keys together and see which ones the keyboard reports. Six letters at once plus modifiers is 6KRO; seven or more means NKRO (N-key rollover). The test also checks eight common game combinations. To find a ghosting combination, hold W A S D and press every other key in turn — any key that fails is blocked.

How to use it

  1. Click the keyboard. Keys are captured only while the picture is active.
  2. Measure rollover. Hold as many letter keys as you can — the eight home-row keys are a good start. Normal keys and modifiers are counted separately.
  3. Try the game combos. Hold all the keys in a card together. It turns green when they all register; tap “Can’t get them all” if one never lights.
  4. Hunt ghosts. Hold W A S D and press every other key in turn. Keys that register turn green on the picture.

Keyboard ghosting test in three parts

  1. Rollover. Hold as many keys as you can. The counters show the most keys reported at once, and how many of those were normal keys rather than modifiers.
  2. Game combos. Eight cards with common combinations — sprint diagonals, jump, crouch-walk and reload, ability keys, and eight home-row keys. Each turns green when every key in it is down at the same time.
  3. Ghost hunt. Hold W, A, S and D and press every other key in turn. This is the quickest way to find a blocked three-key combination.

What is keyboard ghosting?

A keyboard reads its keys through a grid of wires — the matrix. When three or more keys are held, the electrical path through the grid can become ambiguous. Cheaper keyboards then either block one of the keys (it never registers) or show a ghost (a key you did not press). Most modern keyboards block rather than ghost, so in practice an anti ghosting test is a hunt for blocked combinations.

Ghosting is a property of the design, not a fault, and no software can fix it. The fixes are to bind game controls to combinations that pass, or to use a keyboard built with anti-ghosting diodes or N-key rollover.

NKRO test: 6KRO or N-key rollover?

This N key rollover test separates a ghosting keyboard from one that is simply limited to six keys.

The standard USB keyboard report — the one every computer understands from start-up — carries a byte for the modifier keys plus six slots for normal keys. A keyboard using it has six-key rollover (6KRO): six letters at once, with any combination of Shift, Ctrl, Alt and the Windows or Command key on top.

Keyboards with N-key rollover report every key independently. That is why this key rollover test counts normal keys separately from modifiers:

Normal keys at once What it means
2–3 Basic office or laptop keyboard
4–5 Partial rollover
6 6KRO — the standard USB report
7 or more NKRO

If your gaming keyboard stops at six, look for an NKRO mode in its software or manual — many ship in six-key mode for compatibility.

Tips for an accurate keyboard rollover test

  • Avoid Ctrl + W, Ctrl + T, Alt + F4 and the Windows key: the browser or the system acts on them before the page can stop them.
  • Laying a hand flat on the letters is the quickest way to reach seven or more keys.
  • Genuine ghosting is repeatable. If a combination fails once, try it again before rebinding anything.

If something goes wrong

A movement key drops when sprinting

That combination is blocked by the keyboard matrix. Rebind sprint or crouch to a key that passes with WASD held.

Rollover stops at 6

Your keyboard is in six-key (USB boot) mode. Many gaming keyboards have an NKRO toggle — often a key combination in the manual.

Keys stay lit after releasing on a Mac

macOS does not report releasing keys while Command is held. Release Command and the picture resets.

FAQ

What is keyboard ghosting?

Keyboards read their keys through a grid of wires (a matrix). On simpler designs, some combinations of three or more keys either block one of the keys you pressed or make a key you did not press appear. Microsoft’s own demonstration notes that the most straightforward design has thousands of failing three-key combinations.

What is the difference between 6KRO and NKRO?

The standard USB keyboard report has room for six normal keys plus the modifier keys, so 6KRO means six letters at once with any Shift, Ctrl or Alt on top. NKRO (N-key rollover) means every key is reported independently. This NKRO test counts normal keys separately so you can tell them apart: seven or more means NKRO.

How do I find ghosting combinations?

Hold W A S D, then press every other key in turn. If one does not register, release some of WASD to find the exact three-key combination.

Is ghosting a fault?

No — it is how the keyboard was designed. It cannot be fixed in software, but you can bind game controls to combinations that pass, or choose a keyboard sold with anti-ghosting or N-key rollover.

Sources

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Keyboard Test

Press every key on a full keyboard picture — catches dead keys and double typing.

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Keyboard Latency Test

Measure the lag your computer adds between a key press and the next frame.

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Keyboard Polling Rate Test

Estimate your keyboard’s polling rate from how its key timings line up — 125 to 2000 Hz.