How the test works
Press Start and the map takes focus. From then on every key you press is reported to the page by its physical position, the same code whether the keyboard is set to English, Bulgarian or Turkish. The matching key on the map lights up in yellow for as long as you hold it and keeps a lighter tint afterwards, so after a minute of typing you can see at a glance which keys have never been touched. The chip above the map shows how many distinct keys have registered and the last one pressed; on a desktop the history line lists the last twelve.
While the test runs the page swallows what the browser would normally do with a key: Space does not scroll, F11 does not toggle fullscreen, the Windows key does not open the Start menu inside the page, and Alt does not focus the menu bar. Two things are left alone on purpose. Tab still moves focus, so a keyboard user can reach the Stop button, and F5 and F12 keep their reload and developer-tools meaning because the browser handles them before the page can. Every one of those keys is still counted. Two quirks come from the operating system, not the keyboard: AltGr on European layouts arrives as Ctrl and Alt together, so both light up, and macOS reports no key release while Command is held, so the map releases everything when Command comes up.
Pick the map that matches the keyboard: ANSI is the US layout with a wide Enter key, ISO is the European layout with a tall Enter and an extra key next to the left Shift. The full map has a numpad and 104 or 105 keys; the compact map drops the numpad, as on most laptops and tenkeyless boards. The map only changes the picture and the total the result is compared against; every key is counted whatever map is shown.
What the result means
The result is the number of distinct keys that registered during the run, with the context line saying how many of them are on the drawn map, how many presses were made in total and the most keys held at the same time.
- Every key on the map lit. The keyboard's switches and controller are fine. A key that types the wrong character is a language layout setting.
- One key never lights up. The switch or its contact is dead. On a mechanical keyboard the switch can be replaced; on a membrane or laptop keyboard the whole assembly usually is.
- A key lights up on its own, or stays lit after release. A stuck or bouncing switch. Dirt under the keycap or a spilled drink are the usual causes; a keyboard that registers a key you did not press is failing.
- Several keys light up from one press. A short between rows of the matrix, typically after liquid damage.
- "Held at once" is lower than the keys you held. The keyboard has limited rollover. That is normal for office keyboards and only matters for games and fast typing.
What to do about a dead or stuck key
Turn the keyboard over and shake it, then clean around the key with compressed air. Pull the keycap if it is removable and check for crumbs or sticky residue; a cotton bud with isopropyl alcohol cleans the switch stem. On a laptop, check whether the keyboard works in the firmware setup screen: if a key is dead there too, the fault is in the hardware, not in a driver. Try a different USB port or cable, and for Bluetooth keyboards remove the pairing and pair again. If a key works in the firmware screen but not in the operating system, remove and reinstall the keyboard driver and check for accessibility settings such as filter keys, which ignore short presses.
When to return or claim the warranty
A new keyboard with a dead, stuck or chattering key is defective and should be exchanged within the return window rather than repaired. For a warranty claim, screenshot the map after pressing every key so the dark keys are visible, and note whether the key fails in the firmware setup screen as well. Switch failures without physical damage are covered; liquid damage and worn keycaps are not. Laptop keyboards are part of the laptop's warranty, and a single dead key is enough for a repair claim.
Frequently asked questions
A key lights up on the map but types nothing in other programs. Is it broken?
No. The map lights up from the physical key code, which the keyboard sent correctly. What a key types is decided by the language layout of the operating system, so a key that lights up here but prints the wrong character or nothing at all is a layout setting, not a hardware fault. Check the input language in the taskbar or menu bar.
Why do some keys never light up, like Fn, Print Screen or the media keys?
Fn is handled inside the keyboard and never reaches the operating system, so no software can see it. Print Screen on Windows arrives only as a key release, which this test still counts, but the operating system may take a screenshot at the same time. Media and power keys are intercepted by the operating system on many machines; they can show up in the history line with their raw name or not at all.
What does the number of keys held at once mean?
It is the most keys the browser saw pressed at the same time during the run. Office keyboards typically deliver two to six, gaming keyboards with n-key rollover deliver every key. Hold four or five keys in one block, for example Q, W, E and R, and the counter shows how many made it. Fewer than you hold means the keyboard's matrix cannot report that combination.
Can I test a laptop keyboard or a Bluetooth keyboard with this?
Yes, any keyboard that the operating system sees works, including laptop keyboards, Bluetooth keyboards and keyboards connected through a KVM or a USB hub. Choose the compact map if the keyboard has no numpad. Touch-screen keyboards on phones do not report physical keys and are not what this test is for.
Does the test send what I type anywhere?
No. The keys are read by the page only while the test runs, are used to light the map and fill the short history line, and are discarded when you press Stop. Nothing is stored and nothing is sent; the whole page works with the network cable unplugged.