Keyboard Tester

How to Use It

• Press each key once. It lights up while held and stays tinted once tested.
• Pick your layout (Full, UK ISO, TKL, 75%, 65%, 60%, or Mac) so the counter matches your keyboard. On a Mac, see how to test a keyboard on a Mac for Apple's fixes when keys don't respond.
• Hold several keys together to check rollover, then type a sentence to check for doubled letters.

What the Results Mean

Keys Tested

How many keys of the chosen layout have sent at least one press or release. A key that stays gray after you press it firmly is not reaching the computer.

Most Keys at Once

The largest number of keys the page saw held down at the same moment. If it stops at 2 or 3 for some combinations, those keys share a circuit and block each other (ghosting). Office keyboards usually handle 6 keys; many gaming keyboards handle all of them.

Chatter Found

A key that registered a second press within 30 ms of its release. People can't press a key twice that fast, so this is a bouncing switch contact.

Hold Time

In the Key History, how long each key was held, from press to release. A key that shows a short hold when you didn't tap it that fast may be bouncing.

Lock Keys

Three chips under the stats show whether Caps Lock, Num Lock, and Scroll Lock are on or off, updated the moment you press a key. They appear after your first key press; Num Lock and Scroll Lock are hidden on the Mac layout, which has neither.

Fixes

A Key Doesn't Light Up

• Try the key in a text editor. If it works there, the system or browser is catching it first (see the list below).
• Unplug the keyboard and plug it into another USB port, or re-pair it if it is wireless.
• Clean under the key cap with compressed air. On a laptop, check for a stuck or tilted key cap.

A Key Chatters or Types Twice

• Blow compressed air into the switch and press it 20 or 30 times to clear dust from the contacts.
• On a hot-swap mechanical keyboard, replace that one switch.
• Some keyboard software has a debounce setting; raising it can hide mild chatter.
• For connection, settings, and replacement steps, see fixing a keyboard that types double letters.

Keys Browsers Can't Test

• Fn and media keys are handled inside the keyboard or by the system.
• The Windows key opens the Start menu, and some shortcuts (Ctrl+W, Ctrl+T, Cmd+Q, Alt+Tab) act on the browser or system first.
• Print Screen often sends only a release, which still counts as tested here.