This keyboard ghosting test shows, live, every key your keyboard reports while you hold several at once, in the order they arrived. Pick one of 10 combos, hold its keys, let go, and the combo gets a result: all keys registered, a named key that dropped out, or a stop at 6 keys. The combos cover gaming movement, fast typing rolls, modifier stacks and both hands on the home row, so one run tells you how many keys your keyboard handles and which groups it blocks. It works with any USB, wireless or Bluetooth keyboard on Windows, Mac, ChromeOS and Linux. The keyboard picture still lights every key, as in the full keyboard tester.
How to run the anti ghosting test
- Start with the first combo, Sprint diagonally and jump. Hold W, A, Shift and Space together.
- Watch Keys your keyboard reports right now and the Now try panel. Every key you hold should light up there.
- Hold the keys for a moment, then let go. The combo card shows its result, and the test moves on to the next combo once one passes.
- Click any card to try that combo. Repeat a combo that dropped a key to be sure it was not your fingers.
- Finish with Eight fingers on the home row and Home row plus Space. They find your keyboard's limit.
- Press Copy results to keep every combo result with the verdict.
Press Ctrl last in the crouch combo. In some browsers Ctrl + W closes the tab, so while Ctrl is held this page asks before it can be closed. In Chrome and Edge, Lock system keys passes those shortcuts to the page instead.
What the results mean
| Result | What it tells you | Normal result |
|---|---|---|
| Keys held now | How many keys the keyboard reports at this moment | Every key you are holding |
| Most keys at once | The highest count so far, split into keys and modifiers | 6 or more on gaming keyboards |
| All registered | Every key of the combo was down at the same time | Expected on any gaming keyboard |
| A key dropped | The named key did not show while the others were held | A wiring limit on that combo |
| Stopped at 6 keys | Only 6 regular keys showed on a home row combo | A 6 key rollover keyboard |
| Extra key | A key you did not hold appeared during the combo | Ghosting, or a neighbour key pressed by accident |
Ghosting, blocking and rollover
Inside most keyboards the keys sit on a grid of wires, and the controller finds a pressed key by where its row and column meet. Hold three keys that form three corners of a rectangle on that grid and the controller cannot tell whether the fourth corner is pressed too. Old keyboards reported it, which is ghosting: a key you never pressed. Modern keyboards refuse to guess and drop the extra key instead, which is blocking. In a game, blocking feels like a jump or crouch that sometimes does nothing.
Rollover is how many keys a keyboard reports at once, whatever the combination:
| Type | Keys reported at once | Found on |
|---|---|---|
| 2KRO | Any 2 keys plus modifiers, some 3 key combos | Office keyboards, many laptops |
| 6KRO | Any 6 keys plus all modifiers | Many gaming keyboards, and the usual cap over Bluetooth |
| NKRO | Every key you hold | Gaming and enthusiast keyboards, often only over the cable |
Why USB keyboards stop at 6 keys
The basic USB keyboard report, the one every computer and BIOS understands, is 8 bytes long. One byte holds 8 on or off bits for left and right Ctrl, Shift, Alt and Windows or Command, one byte is spare, and 6 bytes each hold one pressed key. Press a seventh key and the keyboard has nowhere to put it, so a standard keyboard sends an error code instead and the computer keeps the last good set. That is why this test shows a stop at exactly 6 keys, while modifiers keep working on top.
Keyboards with n-key rollover send a longer report alongside, or switch to one after the system starts. Some keep the 6 key report by default for compatibility and offer NKRO in their software or through an Fn shortcut listed in the manual. Some KVM switches and adapters only pass the basic report, so a keyboard behind one may stop at 6.
Why Bluetooth often limits rollover
Most Bluetooth keyboards send the same 6 key report, because every phone, tablet and computer understands it. So the same keyboard can show all nine home row keys on its cable and stop at 6 over Bluetooth. Gaming keyboards with a 2.4 GHz dongle vary by model. If a combo fails only without the cable, that is the reason, not a fault.
A combo drops a key
When a combo shows a key dropped, work through the causes from the most likely:
- The keyboard's wiring. Office, laptop and budget keyboards block some groups of three or four keys by design. Retry the combo twice. If the same key drops each time, it is a wiring limit, and the fix is to bind that action somewhere else, such as crouch on C or a side mouse button.
- A 6 key limit. If you hold more than six regular keys, the rest are dropped. Turn on NKRO mode if the keyboard has one, and test again on the cable.
- A weak or dead key. If the card says the key has not registered at all yet, test it on its own in the keyboard tester first. A key that only fails when pressed with others is a rollover limit.
- Software in the way. Keyboard software with a game mode, macros or remapped keys can swallow keys. Close it and test again.
An extra key appears
If a key you did not press shows up while you hold a combo, check your fingers first: a neighbouring key is easy to brush. If it appears every time with the same three keys, the keyboard is ghosting. That is rare on modern keyboards, whose controllers block ghost keys, and it is a reason to replace one used for gaming. A key that lights up with nothing pressed at all is a short, often after a spill, covered in the guide for a keyboard not working.
How to read your result for gaming
Moving in most shooters means W or S plus A or D, with Shift, Ctrl and Space on top: up to five keys, two of them modifiers. If the first two gaming combos pass, your keyboard handles that. A keyboard that stops at 6 is fine for almost all play. Full n-key rollover matters for rhythm games, two players sharing one keyboard and chorded typing.
Laptop keyboards block more combos than desktop ones, and the laptop keyboard test covers their other quirks. On a Mac, Command combos are taken by the system, so the combos here use Control, Option and Shift; the keyboard test mac page explains the rest. Timing matters as much as rollover in fast games: the keyboard latency test reads the steps your keyboard reports in, and the polling rate test does the same for your mouse.
What a keyboard ghosting test cannot see
The page sees what the system passes on, so it cannot tell whether a key was blocked by the keyboard, an adapter or a KVM switch, only that it did not arrive. Fn never reaches the computer, and the Windows key and Command combos are taken by the system first. The test also cannot know which keys you physically pressed. A result only counts once the other keys of the combo were held together for a moment, so a sloppy or partial press does not mark a combo as blocked.
Ghosting and rollover questions
What is keyboard ghosting?
Ghosting is a phantom key press. On a key grid without protection, holding three keys at three corners of a rectangle makes the fourth corner look pressed too. Modern keyboards prevent that by blocking the extra key instead, so what you notice in games is a key that does nothing while others are held.
What is n-key rollover?
N-key rollover (NKRO) means the keyboard reports every key you hold, however many there are. Hold the eight home row keys and then Space in this test: a keyboard with n-key rollover shows all nine.
Is 6 key rollover enough for gaming?
For nearly every game, yes. Moving, sprinting, jumping and crouching together is five keys, and Ctrl, Shift and Alt do not count toward the six. N-key rollover matters for rhythm games, two players on one keyboard and chorded typing.
Why does my keyboard stop at 6 keys?
Standard USB keyboard reports have room for 6 keys plus the modifiers. Most Bluetooth keyboards use the same report. A keyboard with n-key rollover sends a different report, often only over its cable or after you switch it on in its software or with an Fn shortcut.
How do I fix keyboard ghosting?
You cannot change how a keyboard is wired, but you can work around it: move a blocked action to a key or mouse button outside the clash, switch on NKRO mode if the keyboard has one, use the cable instead of Bluetooth, or choose a keyboard sold with n-key rollover.
Does anti-ghosting mean n-key rollover?
Not always. Many keyboards sold as anti-ghosting protect only a group of gaming keys, such as W, A, S, D and the keys around them, and still block other combos. Test the combos you actually use.