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Keyboard Tester

Press each key and watch it light up on the on-screen keyboard to find dead or stuck keys.

Start typing, or click the keyboard below to capture keys like Space, Tab and the arrows.

Scroll sideways to see all keys.

Blue: held down now. Green: tested at least once. Outlined: not pressed yet.

0 of 87 keys tested

Last key pressed

Press any key to see its details.

How to use

  1. Click the on-screen keyboard (or move to it with Tab) so the tester can capture every key, including Space, Tab and the arrow keys.
  2. Press each key on your keyboard once. It turns blue while you hold it and green after it has been registered.
  3. Watch the counter and look for keys that stay outlined after you have pressed them. Those keys are not reaching the computer.
  4. Check the last-key panel to see the exact key, code and modifiers your keyboard sent.
  5. Press Esc to release the keyboard when you are done, or use Reset to start a fresh pass.

How the keyboard tester works

When you press a key, your browser fires a keydown event, and when you let go it fires a keyup event. This page listens for both. Each event carries a code that identifies the physical key, for example KeyA, Digit1, ShiftRight or ArrowLeft. The tester matches that code to the drawn layout, which is a standard US (ANSI) full-size keyboard without the number pad: the function row, the main typing block, the navigation cluster and the arrow keys.

A key is drawn blue for as long as the browser reports it as held, and turns green the first time it is registered. The counter shows how many of the drawn keys you have covered, so a full pass is easy to confirm. Keys outside the drawing, such as the number pad or extra macro keys, still appear in the last-key panel even though they do not count toward the total. The same goes for the extra <> key next to left Shift on European (ISO) keyboards: it is not drawn, but pressing it shows the code IntlBackslash in the details panel.

To stop the page from scrolling or jumping around while you test, the tester cancels the normal action of Space, Tab, the arrows, Page Up and Down, Home, End, Backspace, the function keys, Alt, the Menu key, and ’ and / (which open quick find in Firefox), but only while the on-screen keyboard has focus and only when you are not holding Ctrl or Cmd. Esc always releases focus, so you are never stuck.

Finding dead, stuck and chattering keys

  • Dead key: you press it and nothing lights up. Check it again on another computer to rule out software before blaming the hardware.
  • Stuck key: a key stays blue after you release it. Physically stuck keys often come back after the keycap is removed and cleaned. If only the drawing is stuck, press and release the key once more.
  • Chattering key: one press types two letters in a document. The tester cannot show bounce directly, but you can open a blank text field, press the key slowly ten times and count the characters.

Rollover and ghosting

Cheaper keyboards share wiring between keys, so certain combinations of three or more keys cannot be detected at once. This is called ghosting or limited rollover. Hold the combination you use in games and watch whether every key turns blue together. If one stays plain, choose different bindings or a keyboard that advertises anti-ghosting or n-key rollover (NKRO). Once every key checks out, the typing speed test is a good way to try the keyboard under real typing.

Known browser limits

Some keys never reach a web page: Fn on almost every laptop, brightness and volume keys handled by the system, and sometimes Print Screen. On macOS, letters pressed while Cmd is held do not send a release event, so the tester clears all held keys when you let go of Cmd. Browser shortcuts such as Ctrl+W are reserved by the browser and are deliberately left alone.

Key presses only update the drawing on this page; nothing is saved or sent anywhere.

Frequently asked questions

A key stays outlined when I press it. Is it broken?

Not always. First press it a few times firmly and in the center. If it still does not light up, try the keyboard on another USB port or another computer. If the key fails everywhere, the switch or the membrane under it is likely faulty. A key that works on one computer but not another points to a driver, layout or remapping setting instead.

Why do the Fn key and some media keys never light up?

Many keys are handled by the keyboard itself or by the operating system before the browser sees anything. Fn, brightness, volume and some media keys usually fall into this group, and on some systems Print Screen is taken by the screenshot tool. That is normal and does not mean the key is broken.

How do I test for keyboard ghosting or key rollover?

Hold several keys at the same time, for example W, A, S and D plus Shift and Space. Every key you hold should turn blue together. If one stays outlined while others are held, your keyboard has hit its rollover limit. Many office keyboards register only two or three keys in certain combinations; gaming keyboards often support six or more.

My keyboard uses a different layout. Will this still work?

Yes. The tester identifies keys by their physical position (the code value), so the on-screen key marked Q lights up for the key in that spot even on an AZERTY or German keyboard. The key value in the details panel shows the character your layout actually produced.

What is the difference between key, code and keyCode?

The key value is the character or action produced, such as "a", "A" or "Enter". The code value names the physical key, such as KeyA or ShiftLeft, and does not change with the layout. The keyCode is an old number from earlier browser APIs; it is shown because older games and scripts still rely on it.

Why can't I use Tab to leave the keyboard area?

While the on-screen keyboard has focus, Tab is captured so you can test it like any other key. Press Esc to release focus, then Tab works normally again. Shortcuts with Ctrl or Cmd are never blocked.

How do I find a stuck key?

A stuck key stays blue after you lift your finger, because the keyboard still reports it as held. Press and release it once more: if the drawing clears, only a release event was missed. If it stays blue, or the key keeps repeating on its own in a text field, the switch is physically stuck. Unplug or switch off the keyboard, remove the keycap and clean underneath it.

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