Keyboard Tester — Check Every Key Online

How to use this keyboard test

Press every key on your keyboard one at a time. Each key turns blue while you hold it down and stays green afterwards, so the keys still showing grey at the end are the ones that never registered. Work along each row rather than hunting around, and you will catch a dead key quickly.

A key that never lights up is not responding to the computer at all. A key that lights up but stays blue after you release it is stuck down, which is usually debris under the cap rather than a failed switch. A key that flickers or needs a hard press is a failing switch or a dirty contact.

Why some keys behave oddly here

This test listens for the physical key position rather than the character it produces, so it works the same on QWERTY, QWERTZ, and AZERTY layouts. The letter shown on the tester is the US position; if you press the key where Z sits on a US board, the Z lights up even though your keycap says Y or W.

A few keys never reach the browser at all. Fn is handled by the keyboard controller itself and produces no event, so it cannot be tested here and is not shown. Media keys, screen-brightness keys, and some laptop function keys are intercepted by the operating system before any web page sees them. None of that indicates a fault.

The tester deliberately blocks the normal behaviour of keys like Tab, Space, and the arrow keys while you are on this page, so that testing them does not scroll the page or move focus somewhere else. Any key held with Ctrl, Alt, or Cmd is passed through to the browser untouched, so your usual shortcuts and reload still work.

Ghosting and key rollover

If you hold several keys at once and one of them fails to appear, you have found the limits of your keyboard’s rollover rather than a broken key. Cheaper membrane keyboards share wiring between groups of keys and can only report a few simultaneous presses before combinations start getting dropped or, in the worst case, phantom keys appear that you never pressed. Keyboards advertised as N-key rollover wire each switch independently and do not have this problem. It matters mainly for gaming, where you might hold three movement keys and a modifier at once.

If a key is genuinely dead

Before assuming hardware failure, rule out the cheap causes. Restart the machine. Try the keyboard on another computer, or a different keyboard on this one, which immediately tells you whether the fault is the board or the port. Check that a stray accessibility setting such as Filter Keys or Sticky Keys is not swallowing input. On a laptop, reinstalling or rolling back the keyboard driver resolves a surprising share of cases.

For a stuck or unresponsive key on a mechanical board, prise the keycap off and clear the debris with compressed air. On a laptop, where the keys are far more fragile, our guide to fixing a non-working laptop keyboard walks through the software fixes first and the physical ones last. If only one key has died and everything else works, an external keyboard is very often the cheaper answer than a replacement laptop keyboard and the labour to fit it.

Nothing you type here is recorded or sent anywhere. The test runs entirely in your browser.