Keyboard test
Press every key once. Each one lights up as it goes down and stays marked afterwards, so you can see at a glance which caps you have not tried and which ones never answered.
Press every key. Each one lights up and stays marked.
While this test is focused, keys are captured and will not act on the page. Click outside to release.
Caps read from the keyboard you are using, not from a preset. Pick a layout above to override it.
Nothing in the browser reports which of the two shapes your keyboard is, so this one is your call. ISO has an extra key beside a shortened left Shift; ANSI does not have that key at all.
Choosing a size only changes what is drawn. Every key you press is still measured, including keys this board does not show.
- Keys pressed0
- Last key—
- Held downnone
Did every key you pressed light up?
What the colours mean
A key turns bright while it is held down, and stays marked afterwards. That is the difference between “this key works” and “I have already tried this key”, and it is what lets you find the ones you missed without holding anything.
The counter shows how many distinct keys have answered.
The last key line shows the name the browser uses for the key you just pressed — KeyA, Digit1, ShiftLeft. That name is the key’s physical position on a standard US board, not the letter printed on the cap, which is why it is worth reading rather than ignoring: it tells you what the computer received, independently of what your keyboard is labelled.
Three faults, and which one you have
A keyboard goes wrong in three ways, and they need different tests because they look nothing alike once you know what to watch for.
A key that does nothing. Press it, nothing lights, nothing types. This page finds it.
A key that fires twice. One press, two letters — hhello. The key works, so it passes this test cleanly, and only the chatter test catches it: it measures the gap between presses and a gap below about 70 ms is the switch bouncing, not your finger.
Keys that vanish when held together. Everything works alone, and in a game the third or fourth key is ignored. That is not a fault at all but a wiring limit, and the rollover test measures how many your board can report at once — and whether it ghosts, which is the opposite problem of reporting a key you never pressed.
Run this one first. It is the fastest, and the other two only make sense on keys that answer.
If a key does not respond
Try it in a different application first. Thirty seconds, and it rules out the page and the browser entirely.
Check whether it is dead or reporting elsewhere. Watch the whole board as you press. If some other key lights up, the switch is fine and your layout simply differs from the drawing. If nothing lights anywhere, the key is not reaching the computer at all.
Then it depends on what kind of keyboard you have.
Mechanical. Take the cap off and look — this is the single most productive thing you can do. Crumbs, hair and dried drink under a cap stop a switch mechanically and are far more common than switch failure. Compressed air, cap back on, test again. If it is still dead and the board is hot-swappable, swap the switch with a neighbouring one you rarely use: if the fault follows the switch you have your answer, and if it stays with the position the fault is on the circuit board.
Membrane, and most laptops. There is no switch to swap. Under each key is a rubber dome pressing two printed contacts together, and a dead key is usually contamination on those contacts or a broken trace. Cleaning around the key sometimes works; a spill that has dried usually does not. On a desktop membrane keyboard, replacement is the economical answer. On a laptop, the keyboard is one assembly and replacing it is a repair with a real price — get the quote before deciding, because on an older machine it can approach what the machine is worth.
Any keyboard, after liquid. Unplug it immediately and do not power it on to check. Liquid plus current is what destroys traces; liquid alone often dries harmlessly. The sooner it is disconnected and the longer it dries, the better the odds.
The number pad
Switch it on with the checkbox if your keyboard has one — it is off by default so the count stays honest on laptop and tenkeyless boards, which most visitors have.
Almost every “the number pad stopped working” is one of three things, and none of them is a broken key.
NumLock is off. Those keys have two jobs printed on the same caps: digits with NumLock on, and Home, End, Page Up, the arrows and Insert with it off. Press NumLock and watch it answer here. A reboot, a remote desktop session or another machine’s settings can all leave it flipped without you touching it.
Mouse Keys is on. The pad drives the mouse pointer instead of typing, which people describe as the numbers doing nothing. On Windows it has a shortcut easy to catch by accident — left Alt, left Shift and NumLock together — and it lives under Accessibility, Mouse. On macOS it is Accessibility, Pointer Control.
It is a laptop’s hidden pad. Boards without a separate pad often hide one under the right-hand letters, latched with Fn. If U, I and O type 4, 5 and 6, that is it: find the key marked NumLk, usually sharing F11, Scroll Lock or Insert, and press it with Fn.
If NumLock answers here and the digits still do not arrive anywhere, then the keys are worth suspecting — and the repair advice above applies to them like any other.
Layout, shape and size
Three controls above the board, and none of them touches the measurement.
Layout decides what is printed on the caps. In Chrome and Edge the page asks the browser what the attached keyboard produces and labels itself from that, so the board is yours rather than a guess; the control then says “Detected”, and picking a named layout overrides it. Firefox and Safari have no such API, which is why the presets are there. Overriding matters more than it sounds: the detected answer describes the active software layout, and a German keyboard driven by a US layout is an ordinary situation.
Shape is ANSI or ISO, and it is the one difference here that is physical rather than printed. ISO has an extra key next to a shortened left Shift, and a tall Enter. No browser reports which shape a keyboard is, so this is a question rather than a detection.
Size draws fewer keys: 60%, 65%, tenkeyless and full. It exists so that a small board is not surrounded by keys it does not have, and the count stays honest — the tally always counts the keys actually on show. Press a key the current size leaves out and it still registers; the last-key readout names it and says which size hid it.
75% is deliberately missing. A 75% board and a tenkeyless one have the same keys and differ only in how tightly they are spaced, and this drawing lays keys out in rows without the physical gaps — so offering both would be a choice that changed nothing.
If nothing responds at all
Click the board first: it only listens while it has focus. After that, the order that finds it fastest is connection, power, driver.
Move a wired keyboard to a different port, directly on the machine rather than through a hub. Replace the batteries in a wireless one before suspecting anything else, and move the receiver to a front port away from USB 3 sockets, which are a documented source of interference in the same band. Then, on Windows, delete the keyboard in Device Manager and restart — the driver reinstalls itself and a corrupted one is a real if uncommon cause.
A keyboard that types in the BIOS but not in the operating system is software. One that types nowhere, on two computers, is the keyboard.
None of the first three apply to a laptop, which has no port to move, no batteries and no receiver — and it has causes of its own, from a ribbon cable through the hinge to Fast Startup restoring a broken driver. Laptop keyboard not working is the same diagnosis written for the built-in board.
Windows 11
- Filter Keys — Settings, Accessibility, Keyboard — ignores brief or repeated keystrokes and can make working keys look dead. Confirm it is off before diagnosing anything.
- Sticky Keys changes how modifiers behave and is easy to enable by accident, since pressing shift five times offers it.
- A wireless keyboard that misses scattered keys is usually a receiver problem rather than a switch problem. Move the receiver to a front port, away from USB 3 ports and hubs, which are a well known source of interference in the 2.4 GHz band.
macOS
- Slow Keys, in System Settings, Accessibility, Keyboard, requires a key to be held before it registers and will make quick presses appear dead.
- On a Mac, some function keys act as media controls unless “Use F1, F2, etc. keys as standard function keys” is enabled, which is why they may not appear here.
- MacBook keyboards are a single assembly. A dead key that survives cleaning is usually a case-level repair rather than a component one, which is worth knowing before paying for a diagnosis.
Common questions
The Fn key does nothing. Is it broken?
No, and it cannot be tested here or anywhere else. Fn is not a key the computer ever sees: it is handled entirely inside the keyboard, which uses it to decide what the other keys should send. Press Fn and F5 together and the keyboard sends whatever it decided — a brightness command, or F5, or nothing — but Fn itself is never transmitted. A keyboard tester that appears to light an Fn key is lighting something else. If Fn combinations do not work, the fault is in the keyboard firmware or the manufacturer utility, not in a switch.
What is the code shown beside each key?
The physical position of the key, in the name browsers use for it: KeyA, Digit1, ShiftLeft, Semicolon. It describes where the key sits, not the letter printed on the cap, and the names happen to come from the US arrangement. That is why a French AZERTY keyboard reports KeyQ when you press the key marked A — the position is the same, the printing is not. The board above can be drawn with your printing, and the code stays the same underneath, because the code is the thing being tested.
Nothing happens at all when I press anything.
Click the board first — it only listens while it has focus, and a page that has just loaded does not. If it still does nothing, try the keyboard in any other application: a keyboard that types nowhere is a connection, a driver or a dead keyboard, and one that types elsewhere but not here is a focus problem. On a wireless keyboard, the batteries and the receiver are the first two things to rule out, in that order.
Several keys stopped working at once.
That pattern points at one of three things, and almost never at three failed switches. A spill, which takes out whole rows or columns because it bridges the traces underneath. A ribbon cable, on a laptop, which is a repair rather than a replacement. Or the keyboard matrix, where a broken row makes every key on it silent — and a matrix fault is recognisable because the dead keys line up in a row or a column on the board rather than scattering.
A key lights up in the wrong place. Is my keyboard broken?
No — that is a layout difference, not a fault, and the Layout control above fixes the drawing. In Chrome and Edge the board labels itself from the keyboard you are actually using; in Firefox and Safari there is no such API, so pick UK, German or French from the list and the caps will match yours. Either way the key is working: it reports its position, and only the printing differs.
My number pad types arrows and Home instead of digits.
NumLock is off, and nothing is broken. The number pad keys have two jobs: with NumLock on they send digits, with it off they send Home, End, Page Up, the arrows and Insert — which is why they are printed on the same caps. Press NumLock once and watch it light up here; if it responds and the digits come back, that was all it was. This catches out a great many people after a reboot or a remote desktop session, both of which can leave the state flipped.
The number pad moves the mouse pointer.
Mouse Keys is on. It is an accessibility feature — Windows under Accessibility, Mouse, and macOS under Accessibility, Pointer Control — that turns the number pad into a pointer control, and on Windows it has a keyboard shortcut of its own that is easy to hit by accident: left Alt, left Shift and NumLock together. Turn it off and the pad returns to typing numbers.
Which keyboard shape should I pick, ANSI or ISO?
Look at the Enter key. ANSI Enter is a wide rectangle on one row and ISO Enter is tall, filling two, with the extra key beside a shortened left Shift. Nothing in the browser reports which one you have — the one API that comes close describes the software layout rather than the keys that physically exist, and on a US Mac it reports a character for the ISO key that the keyboard does not have. So this one is asked rather than guessed, and getting it wrong only changes the drawing.
My laptop has no number pad, but the letters sometimes type numbers.
Many laptops without a separate pad hide one under the right-hand letters, reached with Fn, and it can be latched on. If U, I, O turn into 4, 5, 6, that latch is on — look for a key marked NumLk or a padlock with a 1 on it, usually shared with F11, Scroll Lock or Insert, and press it with Fn. The keys report the number pad codes while it is latched, so turning on the number pad above will show you exactly what the computer is receiving.
Some keys do nothing at all — Print Screen, or the media keys.
A few keys never reach the browser. The operating system takes them first: Print Screen, the volume and media keys on many machines, and certain function combinations. That is the system working as designed rather than a keyboard fault.
A key is stuck lit even though I let go.
That is worth investigating. Usually it means the key never sent a release, which happens with a physically sticking key or when focus left the page while the key was down. Click the board and press the key again; if it stays lit a second time, the switch is sticking.
Why do keys get captured while the test is running?
Because otherwise Tab would move focus away mid-test, the function keys would trigger browser features, and the whole exercise would be impossible. Everything is swallowed while the board has focus. Click anywhere outside it to release.