MotionShine01 / Dead keys
Every key marked
A key turns violet once it has worked. Keys still grey at the end did not reach the computer.
Free tool
Keyboard tester, every key, one look.
Press the keys on your keyboard. Each one lights up while you hold it and stays marked once it has worked, so a dead key is easy to spot. The page also counts how many keys work at the same time and flags a key that types twice from one press. Pick the Mac or the Windows layout.
...Press any key
Keys working0
Held now0
Most at once0
Layout
Typing twice
Keys that fired twice in under 60 msNone found
A worn key can send two presses from one tap. If a key shows up here, press it slowly a few more times to be sure.
Options
So Space does not scroll and Tab does not jump away. A few shortcuts, such as quitting the browser, still work.
Key presses are read by this page only. Nothing is recorded or sent.
What it shows
Three checks, one keyboard.
02 / Rollover
Keys at the same time
Hold several keys down. "Most at once" shows how many the keyboard can report together, which matters for games and shortcuts.
03 / Chatter
Keys that type twice
Two presses of one key closer together than 60 milliseconds are much faster than fingers can manage, so the switch is likely bouncing.
Questions
Good to know.
Why do the F keys on my Mac not light up?
On a Mac the top row changes brightness, volume and media by default, and those presses go to macOS, not the browser. Hold fn while you press them, or turn on "Use F1, F2, etc. keys as standard function keys" in System Settings, Keyboard, Keyboard Shortcuts, Function Keys.
Why can the fn key not be tested?
Most computers handle fn inside the keyboard or the system and never pass it to web pages, so no website can see it. It is drawn with a dashed edge for that reason.
A few keys did not light up. Is my keyboard broken?
Not always. The system catches some keys first, such as the Windows key on some PCs, Print Screen, or shortcuts like command and Tab. Try the key in a text editor too. If letters or numbers stay grey here, the key, its switch or the cable is the likely cause.
What does "Most at once" tell me?
How many keys the keyboard reported down at the same moment. Many office keyboards stop at a few keys in some combinations, which is called ghosting; gaming keyboards often report every key. Press the combination you care about, for example W, A and Space together.
What are code and keyCode?
code names the physical key, for example KeyA, whatever language the keyboard types. keyCode is the older number many programs and games still use. Both are shown for the last key you pressed.
Does it work with a non-English keyboard?
Yes. Keys are found by where they sit on the board, so a French or German keyboard lights up the key you pressed even though its letter differs from the printed map.