日本語English

Keyboard Test

Each key lights up on the on-screen keyboard as you press it, so dead keys stand out immediately. Supports US and Japanese JIS layouts with numpad, and measures maximum simultaneous keys and chatter (one press registering twice).

On-device・No upload

Your files and input are processed only inside your browser on this device and are never uploaded to our servers.

While this area is focused, every key you press lights up on the keyboard below.Press Esc twice to leave the test area (Tab is tested like any other key)
Esc
F1
F2
F3
F4
F5
F6
F7
F8
F9
F10
F11
F12
PrtSc
ScrLk
Pause
~`
!1
@2
#3
$4
%5
^6
&7
*8
(9
)0
_-
+=
Backspace
Tab
Q
W
E
R
T
Y
U
I
O
P
{[
}]
|\
Caps Lock
A
S
D
F
G
H
J
K
L
:;
"'
Enter
Shift
Z
X
C
V
B
N
M
<,
>.
?/
Shift
Ctrl
Win
Alt
Alt
Win
Menu
Ctrl
Ins
Home
PgUp
Del
End
PgDn
↑
←
↓
→
Num
/
*
−
7
8
9
+
4
5
6
1
2
3
Enter
0
.
Scroll the keyboard sidewaysPress Esc twice to leave the test area (Tab is tested like any other key)
Keys tested
0 / 104
Pressed now
0
Max simultaneous
0
Chatter detected
0
Last key
—

If “pressed now” is lower than the number of keys you are holding, your keyboard does not register that combination (rollover limit or anti-ghosting).

Event log

Press a key to see events here.

Chatter detection
30 ms

A key that is released and pressed again faster than this is flagged as chatter (human double taps are usually 60 ms or more).

No chatter detected.

Untested keys104 keys left
  • Esc
  • F1
  • F2
  • F3
  • F4
  • F5
  • F6
  • F7
  • F8
  • F9
  • F10
  • F11
  • F12
  • PrtSc
  • ScrLk
  • Pause
  • ~ `
  • ! 1
  • @ 2
  • # 3
  • $ 4
  • % 5
  • ^ 6
  • & 7
  • * 8
  • ( 9
  • ) 0
  • _ -
  • + =
  • Backspace
  • Tab
  • Q
  • W
  • E
  • R
  • T
  • Y
  • U
  • I
  • O
  • P
  • { [
  • } ]
  • | \
  • Caps Lock
  • 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
  • Ins
  • Home
  • PgUp
  • Del
  • End
  • PgDn
  • ↑
  • ←
  • ↓
  • →
  • Num
  • /
  • *
  • −
  • 7
  • 8
  • 9
  • +
  • 4
  • 5
  • 6
  • 1
  • 2
  • 3
  • Enter
  • 0
  • .

Key presses are only displayed on this page — nothing is stored or sent anywhere.

How to use

  1. Choose the layout (US ANSI / Japanese JIS) and key labels (Windows / Mac) at the top. Supported browsers pick the layout automatically.

  2. Click the keyboard to start testing and press keys one by one. Held keys turn blue; keys you have tested turn green.

  3. Check “Untested keys” for anything you missed. A dead key never changes color.

  4. Press several keys together to record “Max simultaneous”. Keys with chatter turn orange.

  5. To finish, press Esc twice or click “Stop testing”.

What it does

Proper Japanese JIS support

Switch between a 104-key US layout and a 109-key JIS layout with ¥, ろ, Muhenkan, Henkan, Kana and Hankaku/Zenkaku keys. Detection uses the physical position (code), so IME state and produced characters do not matter.

Chatter detection with numbers

When the same key is released and pressed again faster than a human can tap (30 ms by default, adjustable 10–100 ms), it is recorded as chatter with the key, count and actual interval. Auto-repeat is excluded.

Rollover measurement

Shows how many keys are held right now and the maximum reached. If it is lower than the keys you hold, the keyboard does not register that combination.

Event log for developers

Every keydown/keyup is logged with key, code, location (left/right/numpad), repeat flag and milliseconds since the previous event.

A clear way out

While testing, Tab, F5 and similar keys are captured as test keys; press Esc twice to leave the test area.

Use cases

  • Check that every key works on a second-hand keyboard or laptop
  • Find out whether a key types twice from a single press (chatter)
  • Measure how many simultaneous keys a gaming keyboard registers (rollover)
  • Inspect for dead keys after a spill or cleaning
  • See the key / code / location values a browser receives (for developers)

Capability matrix

FeatureSupportNotes
US (104) / JIS (109) layouts with numpadSupported—
Pressed / tested / untested displaySupported—
Chatter detection with adjustable thresholdSupported—
Maximum simultaneous keysSupportedGhost keys (phantom inputs) cannot be identified directly
OS shortcuts (Windows key alone, Alt+Tab, Cmd+Tab…)Not supportedThe OS handles them before the browser sees them
Fn and media keys (volume, brightness…)PartialDepends on the model; may appear as keys outside the layout
Phone on-screen keyboardsPartialThey do not report key positions; Bluetooth keyboards work

Limits & notes

  • Keys the browser never receives (OS shortcuts, some Fn keys) cannot be tested.
  • Browser shortcuts such as Ctrl+W, Ctrl+T or Ctrl+N cannot be blocked and may close the tab.
  • On Mac, keys released while Command is held send no keyup, so held keys are cleared when Command is released.
  • Key positions follow common 104/109-key boards; compact or vendor-specific layouts may differ.
  • The event log keeps the latest 200 events.

Privacy & safety

Key presses are only shown on this page as colors and a log — nothing is stored or sent. This is not a key logger; everything is gone when you close the page.

FAQ

What is key chatter?
A fault where one press registers two or more times, usually because of a worn switch. This tool flags a press as chatter when the same key is pressed again within a time no finger can manage (under 30 ms by default) after being released.
The Windows key or PrintScreen does not respond
The OS often handles these before the browser receives them, so it is probably not a hardware fault. Check whether the Start menu opens or a screenshot is taken instead.
How many simultaneous keys are enough?
3–4 keys are fine for typing; 6 or more is comfortable for gaming. Keyboards with N-key rollover (NKRO) register every key you press.
Can I test with an IME turned on?
Yes. Detection uses physical key positions, so it works regardless of the IME. The log will show key as “Process”, so turn the IME off for detailed checks.
Are my key presses stored?
No. They are shown on this page only, never saved or sent, and disappear when you close the page.

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