Keyboard Test — Check That Every Key Responds

Check which keyboard keys respond.

Keyboard layout

Dark = key held now / light = key pressed at least once. If the diagram is wider than the screen, scroll it sideways.

Last key pressed

key (character produced)
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code (physical key position)
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keyCode (legacy, for reference)
-

"code" represents the physical key position regardless of layout, so the same key lights up on both the US and JIS diagrams. "key" can change with the input-method state and other factors.

Simultaneous keys (N-key rollover check)

0 recognized at once
(none)

Hold several keys down and check the count. How many are recognized at once depends on the keyboard's build and connection (not every keyboard supports many keys at once).

Input history (last 20)

    Shows the keys you pressed with timestamps, newest first. If the same key is re-entered in an extremely short interval, it is logged as "⚠ possible chatter (rough guide)". This is only a guide, not a definitive fault.

    About keys that cannot be detected (an honest note)

    Keys like these are taken over by the browser or OS, so this tool may not detect them (the diagram does not light up). Not responding does not always mean a fault.

    • The Fn key, the power key, and some media keys (volume, brightness, playback)
    • Parts of the Windows key and Menu key (when the OS menu opens and focus leaves the page)
    • PrintScreen, Esc and some other keys assigned to browser or OS actions

    During the test, page side effects like F5 reload are suppressed where possible, but Esc and some OS/browser reserved keys may not be fully suppressible. There is no text field on this page, so just press keys and watch the diagram.

    🔒 Keys you press are never sent or saved.

    How to use it — checking that your keys respond

    1. Choose "US (ANSI)" or "JIS (Japanese)" to match your keyboard (most keyboards outside Japan are US/ANSI).
    2. Press the keys you want to check. While held, a key turns dark; when released it turns light (pressed once).
    3. Press every key in turn and look for any that never turn light. When done, "Reset pressed marks" starts over.
    4. Use "Last key pressed" to see what a key is actually recognized as (key / code).
    5. To test simultaneous keys, hold several down and watch the "held" count.

    What this tool can do

    • Defaults to the US (ANSI) layout; a JIS layout (with Hankaku/Zenkaku, Muhenkan, Henkan, Kana and the ¥ key) is available too for Japanese keyboards.
    • Pressed keys light up in real time, and any key pressed at least once keeps a "pressed" mark, which is handy for a full key check.
    • Also shows a rough N-key rollover count, an input history, and a possible-chatter hint (a guide only).
    • Input is never sent to a server — everything runs on your device (in the browser). No install, no sign-up.

    US (ANSI) vs. JIS layout

    The US/ANSI layout is used in English-speaking regions, with a wide Enter key and symbol positions (@ " : and so on) in their US positions. The JIS layout is for Japanese input, with more keys — Hankaku/Zenkaku, Henkan, Muhenkan, Kana and a ¥ key — and a tall Enter key. If the legends on the diagram do not match your keyboard, switch the layout selection. If they still do not match, your keyboard's physical layout and the computer's keyboard-type setting may disagree.

    How to narrow down a key that does not respond

    If one specific key never highlights, narrowing it down in this order helps (a general guide only):

    • Check that the key is not one of the "cannot be detected" keys (Fn and similar — see the note above).
    • For paired keys (Shift, Ctrl, Alt), compare against the side that does respond.
    • Clear dust and debris around the key; reconnect the keyboard (for wireless, change the battery or re-pair).
    • Try another computer or USB port to tell whether it is the keyboard or the computer.

    If none of this helps, worn contacts or age may be the cause, and replacement is worth considering.

    Frequently asked questions

    Are the keys I press recorded or sent anywhere?

    No. Key input is processed entirely inside your browser and is never sent to any server. The on-screen input history clears when you close or reload the page. Even if you type a password, this tool never saves or sends it (only the layout setting — US or JIS — is kept on your device for next time).

    A key does not respond. Is it broken?

    First narrow it down. It can be a fault, but some keys are taken over by the browser or OS and simply cannot be detected here: for example a laptop's Fn key, the power key, some media keys (volume, brightness) and certain single presses of the Windows key may not reach the browser — that is not a fault. On the other hand, if the surrounding keys respond but one or a few specific keys never highlight, that key may have a bad contact (not certain). Comparing paired keys (left vs. right Shift) also helps you narrow it down.

    When I press many keys at once, only some register. Is it broken?

    Not necessarily. Many keyboards have a limit on how many keys they recognize at once, set by the keyboard's build and connection (USB, built-in, and so on). Some recognize only 3-6 keys; others support N-key rollover for many at once. Certain combinations may also fail to register ("ghosting"). If you press many keys at once in games, choose a product that advertises support. The "held" count here gives a rough idea of how many register.

    It showed "chatter". Do I need to replace the keyboard?

    The label is only a rough guide. It appears when a single intended press is registered twice in an extremely short interval, but fast intentional presses or dropped keys can also trigger it, so it does not prove a fault by itself. If it keeps happening on the same key, try clearing dust from around the key, or reconnecting the keyboard (for wireless, change the battery or re-pair). If it still happens often, worn contacts or age may be the cause and replacement is worth considering.

    Some modifier or dead keys behave oddly.

    Keys tied to input methods (IME) can behave specially, and some browsers deliver their signals with different timing than ordinary keys, so unstable behavior does not always mean a fault. To make testing clearer, turn your input method (IME) off while testing.

    Does it work on a phone or tablet?

    The keyboard diagram is shown, but an on-screen (software) keyboard on a phone or tablet cannot be tested meaningfully. If you connect a physical keyboard over Bluetooth or USB, you can check key responses. For testing a physical keyboard, a computer is recommended.

    Prefer the Japanese version? キーボードテスト（日本語版）