Keyboard test: do all your keys work?

Q: Does the test work with a UK, German or French keyboard?

Yes. The test recognises keys by event.code, i.e. by physical position. The labels follow a US QWERTY keyboard, but the key that lights up is always the one you pressed. The character from your own layout is shown under "event.key".

Click into the keyboard area and press every key. Whatever your keyboard reports lights up and stays marked as tested, so dead or sticky keys stand out right away.

How it is calculated

This keyboard tester shows which keys your keyboard actually reports to the computer. The picture shows a full-size US QWERTY keyboard (ANSI) with number pad. Keys are recognised by their physical position, though, so the test works just as well with a UK, German, French or any other layout.

How to test your keyboard

Click into the keyboard area or Tab into it. The border changes colour – the test is active.
Press each key once. The key lights up while held, then stays highlighted with a tick as "tested".
Watch the "Keys tested" count. A key that stays grey although you pressed it reports nothing – dirt, a failed switch, or a key your operating system swallows (see below).
Press Esc to leave the area; "Reset test" starts over.

What do key, code and location mean?

For every key press, the browser supplies several values defined in the W3C "UI Events" standard:

event.key is the character or meaning of the key in your current layout, e.g. "z", "Z" with Shift, or "Enter".
event.code is the physical position, named after the US keyboard. On a German keyboard the key printed Z reports KeyY, because that is where Y sits on a US keyboard. That is why this test uses code: the picture is right whatever layout you use.
event.location tells duplicate keys apart: 0 = standard, 1 = left (left Shift, Ctrl, Alt), 2 = right, 3 = numpad.

On a UK (ISO) keyboard, the extra key next to left Shift (IntlBackslash) is not part of the US picture; it appears under "Other keys detected".

Ghosting, anti-ghosting and n-key rollover

Inside a keyboard, the keys are wired in a matrix of rows and columns. With certain combinations of three or more keys held at once, the electronics can no longer tell exactly which keys are down. The keyboard then either drops a key (blocking) or reports an extra key you did not press (ghosting). Many keyboards block such combinations rather than send ghost keys.

N-key rollover (NKRO) means every key is detected independently, however many you hold. 6KRO means six regular keys plus the modifiers (Shift, Ctrl, Alt, Win) – that is what fits into one report under the USB HID boot protocol many keyboards use.

How to check: hold a combination you actually need – for gaming, say W + A + Shift + Space – and look at "Pressed right now" and the list of held keys. If a key is missing from the list, your keyboard blocks that combination. "Max at once" remembers the highest number.

Honest limits of this test

The browser only sees what the keyboard and operating system pass on. Some keys therefore never arrive, or only half – that is not a fault:

Fn key: handled inside the keyboard and never sent to the computer. Fn combinations (brightness, for example) may arrive as a separate key at most.
Print Screen: on Windows it often reports only the release or opens the screenshot tool. It still counts as tested here.
Windows key, media and volume keys: often intercepted by the operating system. Media keys that do arrive are listed under "Other keys detected".
System shortcuts such as Ctrl + Alt + Del, Alt + Tab or Ctrl + W cannot be caught by any web page.
AltGr on Windows also reports a left Ctrl key – that is normal.
Mac: while Cmd is held, macOS does not reliably report other keys being released. The test therefore releases all keys when Cmd goes up.
On-screen keyboards on phones report no key position. The test is meant for real keyboards, including Bluetooth or USB keyboards on a tablet.

Typical problems

A key does nothing: remove crumbs and dust first (compressed air, turn the keyboard upside down), then test again. On laptops, trying an external keyboard helps separate hardware from driver issues.
Double letters when typing (chattering): tap one key ten times and compare with the "Keystrokes" counter. If it jumps higher, the switch is chattering. Auto-repeat from a held key is not counted.
Wrong characters, but the right key lights up: the hardware is fine and your operating system is set to a different layout. event.key shows which character the system produces.

Checking your mouse next? The CPS test measures how fast you click.

Frequently asked questions

How do I check that every key on my keyboard works?

Click into the keyboard area and press each key once. Tested keys stay marked with a tick, and "Keys tested" shows how many of the pictured keys have arrived. Keys that stay grey are not being reported by your keyboard.

Does the test work with a UK, German or French keyboard?

Yes. The test recognises keys by event.code, i.e. by physical position. The labels follow a US QWERTY keyboard, but the key that lights up is always the one you pressed. The character from your own layout is shown under "event.key".

Why does the Fn key not respond?

The Fn key is processed inside the keyboard and never sent to the computer, so no program or website can see it. That is not a defect.

What is keyboard ghosting?

With some combinations of three or more keys held at once, the key matrix cannot tell exactly which keys are down, so a key goes missing or an extra one appears. Hold your combination and check the "Keys held right now" list.

How many keys can my keyboard register at once?

Press and hold more and more keys. "Max at once" shows the highest number. Six regular keys plus modifiers suggests 6-key rollover; higher values suggest n-key rollover. Which combinations block depends on the wiring, so test the keys you really use together.

Print Screen or the Windows key stays grey – is it broken?

Not necessarily. The operating system often intercepts these keys before the browser sees them (Start menu, screenshot tool). On Windows, Print Screen often reports only the release; it still counts here. If the system function triggers, the key works.

Can I still use the page with my keyboard?

Yes. Keys are only captured while the test area is active. Press Esc to leave it; Tab, Space and all shortcuts then work normally again.

Is anything I type stored or sent?

No. The test runs entirely in your browser. Neither keys nor text are stored or sent to a server; reloading the page starts from scratch.

Sources and legal basis

As of: 27 September 2026