TestMyLaptop TestMyLaptop

Free Online Keyboard Tester — Find Dead & Ghosting Keys

See every key register in real time. Spot dead, sticky, or ghosting keys.

Active Input IDLE
Key Count 0
Latency LATENCY: --ms
Esc
F1
F2
F3
F4
F5
F6
F7
F8
F9
F10
F11
F12
`
1
2
3
4
5
6
7
8
9
0
-
=
Backsp
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
Ctrl
speed

Response Time

Real-time polling rate measurement across browser events.

keyboard_double_arrow_right

Key Rollover

Check for ghosting and N-key rollover hardware limits.

history

Event Log

Full history of keydown/keyup events for debugging.

How it works

Our Keyboard Tester utilizes high-resolution browser event listeners to capture HID signals directly from the operating system's input stack. When you press a key, we measure the delta between the hardware trigger and the browser's execution thread, providing an estimated latency value.

Our visualizer maps KeyboardEvent.code identifiers to an ISO/ANSI hybrid layout. Keys marked in Green have been successfully registered, while the Blue state indicates an active press.

terminal DIAGNOSTIC PROTOCOL
  • > Initializing HID polling...
  • > Calibrating clock reference: HighResTime...
  • > Listening on DOM_KEY_DOWN | DOM_KEY_UP...
  • > Ready for user input.

How to use the keyboard tester

Click anywhere on the keyboard visualizer so it has focus, then press each key on your physical keyboard one at a time. Keys light up green after being pressed, and show blue while actively held. The counter tracks how many unique keys you have tested.

Work your way across every row, including modifiers like Shift, Ctrl, Alt, and the function keys, until the whole board is green.

Reading your results

Key won't light up: That key is not sending a signal. On laptops this is often dust or crumbs under the keycap. On mechanical keyboards it usually points to a dead switch.

Key types twice (chatter): If one press registers as two, the switch is "chattering" — a common aging fault on mechanical switches.

Some presses get missed: Press several keys at once to test rollover. Cheaper keyboards block certain combinations (ghosting), while NKRO keyboards register them all.

Related tools

Frequently Asked Questions

How accurate is the latency test? expand_more
Measurements are accurate within ±2ms, limited by browser event loop cycles and monitor refresh rates. For absolute hardware latency, specialized oscilloscope probes are required.
Does this work on mobile? expand_more
The visualizer is optimized for physical keyboards. While virtual keyboards will trigger some keys, mobile OS layers often abstract input, making latency testing less reliable.
What is Ghosting? expand_more
Ghosting occurs when certain combinations of keys fail to register because of electrical path sharing in the keyboard's matrix. Modern "anti-ghosting" boards avoid this.
Why can't the test detect the Fn key? expand_more
The Fn key is handled at the hardware level and never reaches the browser, so no web tool can detect it. This is normal and not a fault with your keyboard.
What is N-Key Rollover (NKRO)? expand_more
NKRO means every key press is registered independently, regardless of how many keys are held simultaneously. Most gaming keyboards support this. Press multiple keys at once to test your keyboard's rollover limit.