Keyboard test: do all your keys work?

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

1. Click into the keyboard area or Tab into it. The border changes colour – the test is active.
2. Press each key once. The key lights up while held, then stays highlighted with a tick as "tested".
3. 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).
4. 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" – or switch the view to “ISO”. The key names come from the W3C specification UI Events KeyboardEvent code Values (current W3C version, 2026).

Which picture fits your keyboard?

A laptop has fewer keys than any of these pictures, so “Keys tested” will rarely reach the maximum. What counts is that every key you actually have turns green.

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. The USB HID specification 1.11 (Appendix B and C) defines that report as one modifier byte, one reserved byte and six key bytes, and states: “The limit is six non-modifier keys”. Press a seventh, and the keyboard reports an error state (ErrorRollOver) instead of the keys.

Worked example: is this a chattering key?

The test remembers when each key was released. If the same key goes down again less than 30 ms later, it counts as a double press:

1. You press A at 0 ms and release it at 80 ms. Keystrokes: 1.
2. The switch bounces and reports A down again at 100 ms.
3. Gap: 100 ms − 80 ms = 20 ms. 20 is less than 30, so the press is counted under “Double press detected” and the key gets an exclamation mark. Keystrokes: 2.
4. Compare: a deliberate second tap comes much later. Released at 80 ms, pressed again at 250 ms = 170 ms gap – not counted as chatter.

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.
• Latency and polling rate are not measured by this test – it checks whether keys arrive, not how fast.

Common mistakes when testing a keyboard

• Testing without clicking into the area first: until the border changes colour, key presses go to the browser, not the test.
• Calling a 6-key limit a defect: if the seventh regular key does not light up, the keyboard works as designed for 6KRO.
• Testing ghosting with random keys: blocking depends on the matrix wiring. Test the combinations you really use, such as W + A + Shift + Space.
• Holding a key to test chatter: auto-repeat is ignored. Tap the key 20 to 30 times instead.
• Blaming the hardware for wrong characters: if the right key lights up, check the keyboard layout in your operating system.

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 mouse test checks buttons, double clicks and the wheel, and the CPS test measures how fast you click. Once every key works, measure your speed in the typing test.

Frequently asked questions

Sources and legal basis

• MDN Web Docs: KeyboardEvent.code (physical key position)
• W3C: UI Events KeyboardEvent code Values
• W3C: UI Events – keyboard events (keydown/keyup)

As of: 6 October 2026 · Editorial policy