Keyboard Tester

A keyboard tester that shows you the key, not a status message

This keyboard tester checks every key on your keyboard from inside the browser. Press a key and the matching cap above sinks, the way the real one does under your finger. Keys you have already pressed stay marked, so you can work across the board at your own pace and see exactly what is left. A cap that never sinks is a key that never reached the browser, and that is usually the whole answer: one dead switch, found in about ten seconds, without installing anything.

There are three ways a keyboard goes wrong, and they are not the same problem. A key can be dead, and never report at all. It can be stuck down, reporting continuously while you are not touching it. Or it can chatter, firing twice from a single press. Most online testers only find the first one. This tester marks a stuck key after fifteen seconds of being held, and flags a second press landing within forty milliseconds of the last release as chatter, because no human double tap is that fast. Each of the three has a different cause and a different fix.

Pick the layout in front of you

Keyboards are not all the same shape, and a tester that only draws a standard American 104-key board is not much use if you are holding something else. Six layouts are drawn here, and each one has its own page with the tester already set to it:

• Full size keyboard test. All 104 keys, the number pad included. Press each one and the cap sinks; anything that stays up never reached the browser.
• TKL keyboard test. Eighty-seven keys: everything a full size board has except the number pad.
• 65% keyboard test. Compact, but it keeps the arrows. Press every key, including the right-hand column most people never check.
• 60% keyboard test. Sixty-one keys and nothing else. Everything the board dropped now lives on a layer.
• ISO keyboard test. The UK and European layout, with the tall Enter and the extra key beside the left Shift.
• Mac keyboard test. For a MacBook or a Magic Keyboard, including the modifiers macOS handles differently from Windows.

If your board is not quite any of these, test it anyway. The readout below the keyboard names whatever key actually arrived, including keys the drawn layout does not have, so a slightly unusual right-hand column or a manufacturer-specific key still tells you what you need to know.

What the numbers under the keyboard mean

Untested counts the keys this layout has that have not reported yet. It deliberately excludes keys a browser cannot see, so a healthy full size keyboard really can reach zero rather than stopping at four. Working counts everything that reported cleanly. Faulty appears only when something is chattering or stuck.

Keys at once is the most keys you have held simultaneously during this session, and it is the quickest way to learn something real about your hardware. A cheap membrane keyboard usually stops at two or three. A great many keyboards stop at exactly six, which is not a defect but the size of the standard USB keyboard report. Going past six means the keyboard has full N-key rollover. Try holding W, A, Shift and Space together, the combination games actually use, and see what survives.

The live readout, and the difference between a key and a character

Under the counters, the tester shows four things about the last key you pressed: its physical position, the character it produced, the legacy numeric code, and how long you held it.

The first two are the interesting pair. The position never changes. The character depends entirely on the keyboard layout your operating system is set to, which is why a UK keyboard on a US layout puts the at sign and the double quote in the wrong places and types a backslash where the hash should be. Nothing is broken in that situation and no amount of cleaning will help. If the position is right and the character is wrong, change the layout setting. If the position never appears at all, then it is the key.

Keys that will not report, and why that is normal

Some keys cannot be tested in a browser and are drawn with a dashed outline so you do not go hunting for a fault that is not there. The Fn key on a laptop is resolved inside the keyboard controller and never reaches the operating system at all. Print Screen is usually taken by the system or a screenshot utility first. The Windows and Command keys often open a system menu rather than reaching the page. Media and brightness keys are handled the same way on most machines. None of these silences means a failure, and none of them counts against the untested total.

When the test finds something

The pattern matters more than the individual key. One dead key with working neighbours points at that switch, or debris under it, or a bad solder joint. A whole row or column gone points at a trace or a controller pin, and on a laptop usually at the ribbon cable connector rather than the keys. A scattered but consistent set of failures suggests liquid that spread along the board. Every key dead means a cable, a port or a driver long before it means the keyboard.

Before opening anything, three cheap checks are worth the two minutes: plug the keyboard into another computer, try a different USB port directly on the machine rather than through a hub or monitor, and turn off Sticky Keys and Filter Keys if either has been enabled by accident. A keyboard that works on another machine has told you the fault is not in the keyboard.

• Keyboard ghosting test. Hold several keys at once. If one of them stops reporting, your keyboard cannot see that combination.
• N-key rollover test. Hold down as many keys as your fingers allow. The counter tells you how many your keyboard is willing to report at the same time.
• Key chatter test. One press, two characters. Chatter is a switch problem, and it is one of the few keyboard faults that gets worse over time.
• How to find a stuck key. A key held down without you touching it explains a surprising number of computer problems.
• Keyboard keys not working. Which keys failed tells you more than the fact that they failed. Test first, then read the pattern.
• Keyboard key codes. Every key press gives a browser three different values. They mean different things, and only one of them is about the physical key.

Buying a used keyboard, or checking a new one

The other reason to run a full pass is that the keyboard is not yours yet, or is brand new. A second-hand mechanical keyboard can look immaculate and still have a chattering switch that only shows up after twenty presses, and a freshly built or freshly soldered board frequently has one joint that did not take. Working across every key in order, rather than typing a sentence and calling it fine, finds both in a couple of minutes.

Privacy

Everything happens inside your browser. Key presses are not transmitted, stored or logged anywhere, there is no account and nothing to upload, and closing the tab ends the test with nothing left behind. That matters more than usual for a tool like this one, because the thing being measured is literally everything you type.