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.
- 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.
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.
Take the cap off and look. On a mechanical keyboard this is the single most productive thing you can do. Crumbs, hair and dried liquid under a cap stop a switch mechanically, and they are far more common than switch failure. Compressed air, then the cap back on.
Check whether it is really dead or just reporting elsewhere. Watch the board as you press: if some other key lights up, the switch is fine and the layout differs from the drawing. If nothing lights anywhere, the key is not reaching the computer.
Then suspect the switch. On a hot-swappable board, swap it 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 board itself.
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
A key lights up in the wrong place. Is my keyboard broken?
No — that is a layout difference, not a fault. This board is drawn as a US layout, and the test identifies keys by their physical position rather than the letter printed on them. On a UK, German or other layout some caps sit in different places, so the key you press lights the position it occupies in the US arrangement. The key itself is working correctly.
Why is the number pad not shown?
Because most keyboards that end up here are laptop or tenkeyless, and drawing keys that do not physically exist would make the "keys pressed" count meaningless. The keys that are drawn are the ones nearly every keyboard has.
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.