How this keyboard test works
Every time you press a key, your browser fires a keyboard event that names the physical key
(event.code), the character or action it produced (event.key), and whether it is
auto-repeating. This page listens for those events on the whole window, lights the matching key on the picture,
and keeps it marked after you let go. Type across the whole board and any key that stays dark is one your
computer never heard from. No permission is needed, nothing is sent anywhere, and it works the moment the page
loads.
The page also stops the browser from acting on most keys while the keyboard is on screen, so you can test Tab, Space, Backspace, the arrows and the F-keys without the page jumping or a search box opening. Scroll the keyboard out of view, or press Capturing keys: on to pause, and your shortcuts come back.
Reading the readouts
- Last key is the large readout: the key name, and beneath it the physical code.
- event.key is what your operating system's layout produced. Shift changes it, Caps Lock changes it, a German layout changes it. This is what a text field receives.
- event.code is the physical position in US-layout names, unaffected by language. This is what games and shortcut systems use, and what lights the keys here.
- keyCode is the old numeric identifier some software still relies on. It is deprecated but people ask for it, so it is here.
- location tells left from right for paired keys such as Shift and Ctrl, and marks numpad keys.
- Rollover now / max counts keys currently held and the most held at once during this session.
- Keys tested counts distinct keys seen so far out of the keys drawn on the picture.
Rollover and ghosting
Hold down A, S and D, then add F, G and H. On a basic keyboard the count stalls at two or three, and on some boards a fourth press produces a key you did not touch, called a ghost. That is the matrix inside a cheap keyboard running out of unique paths. Gaming keyboards, most mechanical boards and Apple's keyboards handle six or more, and boards advertising NKRO handle everything. If you play games or type very fast, this readout tells you whether the hardware can keep up. Note that some laptop keyboards report high rollover on letters but drop combinations involving the arrow cluster; test the keys you actually use together.
ANSI or ISO
ANSI is the US-style layout with a wide, single-row Enter and the backslash above it. ISO, common in the UK and continental Europe, has a tall Enter, a key beside left Shift, and moves the hash or backslash next to Enter. The toggle only changes the picture, never the detection, so a key that lights in the wrong place is a layout mismatch, not a fault. The page guesses from your browser language and gets it right most of the time.
Keys not registering? Fixes by browser and system
Unlike the mic and camera, the keyboard needs no permission, so problems fall into three groups: the browser kept the key, the operating system remapped or filtered it, or the hardware is genuinely at fault. Your platform is marked below.
Chrome and Edge browser
Shortcuts that never reach the page: Ctrl+T, Ctrl+W, Ctrl+N, Ctrl+Shift+T, Ctrl+Tab, and on Windows the Win key alone. Ctrl+W will close this tab, so please do not test it here.
Focus. If nothing lights at all, click anywhere on the page first. A focused address bar or omnibox swallows every key. On Chromebooks, the search or launcher key sends MetaLeft, and the top-row keys send browser and media codes rather than F1 to F12 unless you hold the search key or change the setting in ChromeOS keyboard preferences.
Extensions. Vim-style navigation extensions, password managers and some accessibility tools intercept keys. Try an incognito window if presses seem to vanish.
Firefox browser
Shortcuts that never reach the page: Ctrl+T, Ctrl+W, Ctrl+N, Ctrl+Tab and the Alt key alone on Windows, which opens the menu bar. Firefox's quick-find keys (/ and ') are held back by this page so they light normally.
Caret browsing. Pressing F7 in Firefox offers to turn on caret browsing; the page prevents that while the keyboard is on screen, but if you accepted it earlier, arrows will move a text cursor instead of lighting keys. Press F7 again to turn it off.
Safari browser
Shortcuts that never reach the page: ⌘+Q, ⌘+W, ⌘+T, ⌘+N, ⌘+H, ⌘+Tab, ⌘+Space, and Fn or the Globe key on their own.
Function keys. On a Mac, F1 to F12 act as brightness, Mission Control and media keys unless you hold Fn. To make them plain function keys, turn on Use F1, F2, etc. keys as standard function keys in System Settings, Keyboard, Keyboard Shortcuts, Function Keys.
Caps Lock on macOS fires a key-down only when it turns on and a key-up when it turns off, so it may look stuck for a moment; the page releases it automatically. Holding ⌘ can suppress key-up events for other keys until you let go of ⌘; the page clears held keys when that happens.
Windows system
Filter Keys and Sticky Keys. Settings, Accessibility, Keyboard. Filter Keys ignores brief or repeated presses and is easy to enable by accident (holding right Shift for eight seconds turns it on). Sticky Keys makes modifiers latch. Turn both off if keys seem delayed, missing or stuck.
Language and layout. The language indicator on the taskbar (or Win+Space) switches layouts. Wrong characters, or a swapped Y and Z, mean the wrong layout is active, not broken keys. Remove layouts you do not use in Settings, Time & language, Language & region.
Gaming mode and Fn lock. Many gaming keyboards have a mode that disables the Win key, and many laptops have an Fn lock (often Fn+Esc) that swaps the top row between F-keys and media functions. Both look like dead keys and are not.
Wireless. Replace batteries or charge, move the receiver to a port on the computer itself rather than a hub, and re-pair. USB 3 ports and drives can interfere with 2.4 GHz receivers; try a USB 2 port or a short extension cable.
Drivers. A keyboard that fails everywhere: Device Manager, Keyboards, right-click, Uninstall device, then restart so Windows reinstalls the standard driver. Manufacturer software (Razer Synapse, Logitech G Hub, Corsair iCUE) can also remap keys; check its profiles.
macOS system
Slow Keys and Sticky Keys. System Settings, Accessibility, Keyboard. Slow Keys adds a delay before a press counts and makes fast typing drop letters. Turn it off if keys feel unresponsive.
Input source. The menu-bar flag or Ctrl+Space switches input sources. If letters come out wrong, you have switched to another language or a Dvorak/Colemak layout.
Modifier remapping. System Settings, Keyboard, Keyboard Shortcuts, Modifier Keys lets you swap Caps Lock, Control, Option and Command per keyboard. A remapped key lights up in its new role here, which is correct behaviour and easy to mistake for a fault. Karabiner-Elements does the same at a lower level.
Keyboard Viewer. A quick second opinion lives in the input menu: enable "Show Input menu in menu bar" under Keyboard, Input Sources, then choose Show Keyboard Viewer. If a key lights there but not in the browser, the browser or a shortcut is the reason; if it lights nowhere, the hardware is.
Butterfly and dust. On 2016 to 2019 MacBooks with butterfly keys, a repeating or dead key is a known hardware fault that Apple repaired under a service programme; on any laptop, compressed air at a low angle is worth a try before anything else.
iPad, iPhone and Android mobile
On-screen keyboards do not send physical key codes, so use the tap here and type box: each character lights the matching letter. Hardware keyboards connected by Bluetooth, USB-C or a Smart Connector send real events, and this test works with them in Safari and Chrome. On iPadOS the Globe key, ⌘+Space, ⌘+Tab and ⌘+H are handled by the system. On Android, some keyboards send Unidentified for keys the OS does not map; the readout will say so.
Frequently asked questions
A key does not light up. Is it dead?
Maybe, but check three things first. Is it a combination the browser keeps for itself (the list above)? Does the key exist on the layout you selected (ISO boards have an extra key left of Z and a tall Enter; ANSI has a wide backslash above Enter)? And does it fail in a text editor too? A key that fails everywhere, on a wired keyboard, after a restart, is a hardware fault: a dirty or worn switch, a torn membrane, or a broken trace. A key that fails only in the browser is a shortcut or a focus problem, not damage.
What is rollover, and what number should I expect?
Rollover is how many keys the keyboard can report as held down at the same time. Cheap membrane keyboards and many laptops manage two or three plus modifiers before extra presses vanish or ghost keys appear. USB keyboards in basic "boot" mode report six keys plus modifiers, so 6 (or 6 plus Shift, Ctrl and Alt) is a common maximum. Gaming and mechanical keyboards advertising NKRO (n-key rollover) will let you rest a whole hand on the board and count every key. Press several letters at once and watch the Rollover now / max readout.
What is the difference between event.key and event.code?
event.code names the physical position of the key, always in US layout terms: the key left of Enter on the home row is Quote whether your layout prints an apostrophe, an ä or a ç on it. event.key is what that key produces with your current OS layout and modifiers: "a", "A", "ä", "Enter", "ArrowUp". This test lights keys by code, which is why it works with any language layout, and shows both values so you can see what software receives.
Why does the Fn key never register?
On almost every keyboard the Fn key is handled inside the keyboard's own controller. It changes what the other keys send and never reaches the operating system, so no software, this page included, can see it. If Fn seems broken, test a key it modifies instead: hold Fn and press a brightness or volume key and see whether the effect happens.
My layout is not US English. Does the picture still make sense?
Yes. Keys light by physical position, so pressing the key that is Q on a US board lights the Q position even if your layout calls it A. Choose ISO for the tall Enter and the extra key beside left Shift that most European and UK boards have; the test picks it automatically for many locales. The event.key readout shows the character your OS actually produced, so a key that types the wrong letter is a language-layout setting in the OS, not a hardware fault.
Keys type the wrong characters, or type double. Is the keyboard broken?
Wrong characters (y and z swapped, @ and " swapped) are almost always the OS input language: check the language indicator in your taskbar or menu bar. Double letters, or a key that "chatters", is a hardware symptom on mechanical keyboards (a switch bouncing) and on some laptops with debris under a key. Watch the Repeat readout: a genuine double press shows two separate key-downs, while held-key auto-repeat shows yes.
Can I test a laptop, wireless or Bluetooth keyboard here?
Yes, anything the operating system treats as a keyboard. For wireless boards, low batteries cause intermittent missed keys long before the keyboard stops entirely, so swap them before assuming a fault. Bluetooth keyboards paired to a phone or tablet work too: open this page in the phone's browser and type; on-screen keyboards will not show real key codes, so use the "tap here and type" box for those.
How do I fix a dead key?
Compressed air around the key first, angled from several directions. On a mechanical keyboard, pull the keycap and clean or, on a hot-swap board, replace the single switch. On a laptop, a stuck or dead key is usually a repair-shop job or a keyboard-deck replacement, so plug in an external keyboard to keep working while you decide. Remapping software (PowerToys Keyboard Manager on Windows, Karabiner-Elements on macOS) can move a rarely used key onto the dead position in the meantime.