Keyboard Tester

How to test a keyboard

1. 1

   Press Start testing. Until you do, the page ignores your keyboard completely.

2. 2

   Work along each row and watch its twin light up. A key that never lights is the one to look at.

3. 3

   Let go and check. A key that stays lit after you release it never told the browser it came back up, which is what a sticking switch looks like.

4. 4

   Hold several keys at once and watch "Most at once". That is your keyboard's rollover: how many simultaneous keys it can report.

5. 5

   Press Escape or Stop testing when you are done.

What the results mean

A key that lights reliably is working as far as any program on your computer is concerned. A key that lights only when pressed hard, or in one corner, is usually dirt or a worn switch rather than a dead one. A key that never lights may not be broken at all: your operating system may be taking it first.

Rollover is the number of keys a keyboard can report at the same time. Many membrane keyboards manage only a handful, and often refuse particular combinations rather than a fixed number, which is why the count moves around as you try different groups. If a game keeps missing a direction while you hold two other keys, this is the reason.

Keys this page cannot see

A browser only hears what the operating system passes on. The Windows or Command key, media and brightness keys, some Fn combinations, and shortcuts the system claims for itself may never reach this page. Nor does the page suppress anything that closes a tab or window, so those combinations still do what they always do. Screen readers and other assistive software may also take keys before the page sees them.

While the test is running, keys that would scroll or navigate the page are held back, but only those, and only while the test is on. Tab is never held back, so you can always move on to the next control.

For the other half of the desk, use the Mouse Tester, and if one click is arriving as two, the Double Click Test.