Look for phantom keys
Hold a chord and watch the detected list. If a key you never pressed appears, that is a visible phantom key event at the OS level.
Keyboard Ghosting Test
Ghosting happens when a keyboard matrix produces or drops keys in certain combinations. This workspace shows the combination currently detected and explains browser limitations clearly.
Mobile note: Ghosting detection requires a physical keyboard.
esc F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12
` 1 2 3 4 5 6 7 8 9 0 - = backspace
tab Q W E R T Y U I O P [ ] \
caps A S D F G H J K L ; ' enter
shift Z X C V B N M , . / shift
ctrl win alt space alt win menu ctrl
Detected state
Browser view Current held 0
Maximum held 0
Held keys None
Limitations: this panel reports keyboard events delivered by the operating system to
this browser tab. It cannot measure hardware matrix behavior, firmware promises, USB polling, or true
physical latency.
About this test
Drops are also evidence
A key that stops reporting while others stay held can indicate matrix limitations, though shortcuts and focus loss can look similar.
Keep claims honest
A browser cannot inspect the hardware matrix. It can only report the keyboard events the OS delivered to this page.
Run a useful comparison
Compare the held-key list with the keys you deliberately press. A missing intended key and an unexpected extra key are different observations. Repeat the smallest problematic combination in both press orders before describing it as ghosting.
If the list stays empty, first verify a single ordinary letter. If a combination differs between attempts, record the operating system, browser, keyboard layout and connection, then change just one variable. A browser observes delivered events, not the keyboard matrix or firmware, so a missing event alone cannot identify the faulty component.
Browser event background: physical key codes and automatic repeat events. For a missing key, follow the step-by-step comparison procedure.
Related tools
Related guides
Is ghosting the same as rollover?
No. Rollover concerns simultaneous-key reporting. Ghosting means an unexpected phantom key; a missing key in a combination is a separate observation often called blocking. Browser observations alone do not establish the cause.
Can the test fix ghosting?
No. It is a diagnostic tool. If you see consistent phantom keys, try the same chord on another keyboard before assuming the board is at fault.
What causes keyboard ghosting?
A keyboard matrix can produce phantom keys or block some combinations. This page observes events delivered by the browser; it cannot identify a circuit, missing diode, or hardware fault from those events alone.
How do I use a keyboard ghosting test?
Hold a small combination such as W and A, then add Shift or Space one at a time. Note missing or unexpected highlights, release all keys, and repeat. Focus changes, shortcuts, remapping, and the OS can also change the events received; an anomaly is not a hardware diagnosis.
What does anti-ghosting mean for a keyboard?
Anti-ghosting is a manufacturer claim about handling certain combinations without phantom presses. Its coverage varies and does not necessarily mean full N-key rollover. This test records how your chosen combinations reach this browser session; it cannot certify the advertised hardware capability.