How to test a keyboard
Click the tester once so it has focus, then press every key in turn, left to right and row by row. Each key lights up while it is held and stays tinted once it has been tested. When you have been round the whole board, any key still dark is the one to look at.
Then hold down several keys at once, for example A, S, D, F and J, K, L, to test rollover. The "most at once" figure shows how many the keyboard reported together. If you type fast, a keyboard that drops keys when two are held together will cost you letters, especially on rolls like "th" and "ing".
Common keyboard faults
- A dead key never lights up. Check it is not remapped in your system settings, then try another USB port or cable. On a mechanical keyboard, the switch may need cleaning or replacing.
- A key that types twice is called chatter. It usually comes from dust or a worn switch. The tester flags any key that fires twice within 30 milliseconds.
- Keys that drop when pressed together point to a keyboard with limited rollover, or ghosting, where a third key in a certain combination simply does not register.
- A sticky key stays lit after you let go. Watch for a key that does not go dark on release.
Keyboard working? Put it to use
Take a typing speed test to see how fast you are on it, or try Key Reflex, which lights up one key at a time on a 3D keyboard and times how quickly you find it. If you are choosing a new keyboard, our guide to keyboard layouts compares QWERTY, Dvorak and Colemak.
Questions people ask
How do I find a dead key?
Press every key once. Each one you press stays lit. Any key still dark at the end did not reach the browser: it may be broken, remapped, or taken by your operating system before the page sees it.
What does 'typed twice' mean?
Some worn or dirty switches send two presses for one, a fault called chatter. The tester flags a key that fires twice within 30 milliseconds, far faster than anyone presses a key on purpose.
What is key rollover?
Rollover is how many keys a keyboard can report at the same moment. Hold several keys down together and the tester shows the most it saw at once. Many office keyboards stop at around six; gaming keyboards often register every key.
Why do some keys not show up?
Browsers never see a few keys: Fn, and some media or system shortcuts handled by the operating system. On a Mac, the Command key can also hide the key pressed with it.