What does this keyboard test check?

The test listens for the physical key you press (its key code), not the letter it types. That means a German, French or Arabic layout tests the same way as an English one. It checks three things: whether each key responds at all, how many keys your keyboard can register at the same time (rollover), and the exact code your computer receives for each key, which helps when a game or program says a key is "unbound".

How to test your keyboard

Click anywhere on this page so it has focus.
Press each key once. Watch it turn green on the picture of the keyboard.
Any key that stays grey after you press it didn't send a signal. Press it a few more times to be sure.
To test rollover, hold down several keys together, such as A, S, D, F and J, and read "Most at once".

What is keyboard ghosting and rollover?

Rollover is how many keys a keyboard can report at the same time. Many office keyboards handle only 2 or 3 keys at once in some combinations, while most gaming and mechanical keyboards handle 6 or more (often called "6KRO" or "NKRO" for any number). Ghosting is when a key you hold isn't reported, or a key you didn't press appears, because the keyboard ran out of rollover. If "Most at once" stops climbing while you add fingers, you've found your keyboard's limit for that combination.

A key isn't working. What should I try?

Test the same keyboard on another computer. If the key works there, the problem is a setting or driver, not the keyboard.
Check for a function lock (Fn Lock) or a keyboard app that remaps keys.
On a mechanical keyboard, a stuck or dusty switch is common. Remove the keycap and clean around the switch.
For a wireless keyboard, charge it or change the batteries. Low power often makes single keys drop out.

Keyboard works? Test your typing

Once every key is green, see how fast you type with the free typing test, or learn proper keyboard typing from the home row up in the touch typing course.