Key Tester
To test a single key, press it and look at the large display. It shows which key the browser received, its code, whether it is the left or right version, how long you held it and how many times it repeated. If nothing appears when you press a key, the key or the keyboard is not sending it.
Single key tester
You need a physical keyboard for this test. On a phone or tablet, connect a keyboard by Bluetooth or USB first. The on-screen keyboard of a phone does not report which physical key you pressed.
- event.key
– - event.code
– - Location
– - keyCode (old)
– - Presses of this key
– - Last hold
– - Auto-repeats
– - Modifiers on
–
History
Where the key is
You need a physical keyboard for this test. On a phone or tablet, connect a keyboard by Bluetooth or USB first. The on-screen keyboard of a phone does not report which physical key you pressed.
Click here first, so the page receives your key presses.
The page lost focus, perhaps because of Alt+Tab, the Windows key or a shortcut. Click anywhere on the page and continue.
- Held now
- Worked
- Suspected double press
- Held 2 s or longer
- Not pressed yet
- Usually invisible to browsers
Last keys
Keys that are not on this picture
How it works
Press keys on your keyboard. Each key lights up on the picture while you hold it and stays teal once it has worked. The page reads the key events your browser already gives every web page and never sends them anywhere.
This test needs JavaScript. The explanations below work without it.
How to do it
- Click once on the page.
- Press the key you want to test.
- Read the key name, code and location.
- Press it a few more times and check that the counter rises by one each time.
What the fields mean
- event.key: the character or key name your layout produces, such as
"a","A"or"Enter". - event.code: the physical key position, such as
"KeyA", independent of language. - Location: Left or Right for keys that exist twice (Shift, Ctrl, Alt), Numpad for the number pad.
- keyCode: an old number some games and programs still use.
- Auto-repeats: the extra events your system sends while you hold a key. A key that repeats without you holding it may be stuck.
Typing the wrong character?
If event.code is right but event.key is not what is printed on the key, your keyboard is fine and the input language or layout setting is wrong. Change it in Windows under Settings, Time and language, or on a Mac under System Settings, Keyboard, Text Input.
Frequently asked questions
How do I test one key on my keyboard?
Press the key on this page. The large display shows the key name and the fields below show its code, location and hold time. Press it several times: the press counter should go up by exactly one each time.
What is the difference between key and code?
event.key is the character your keyboard layout produces, so it changes with language and Shift. event.code is the physical key position and stays the same, for example KeyQ for the key that types A on a French keyboard.
Why does one press count twice?
If the counter jumps by two for one press, the switch is probably bouncing. Run the double typing test to measure it and see the fix guide for what to do.
Last updated: November 2, 2026