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Input devices

Keyboard Tester

Check every key registers.

Live key & code readout N-key rollover Nothing logged

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Click the keyboard, then press keys Reset

Some keys are reserved by your browser or OS — F11, F5, the Cmd/Win key and certain shortcuts may never reach this page. If a key won't light up here, try it in a plain text editor before assuming it's broken.

Physical keys, not characters.

DeftGauge maps the on-screen keyboard by physical position using the browser's event.code, so the layout lights up correctly whether you're on QWERTY, AZERTY, Dvorak or a non-US layout. The character a key produces can change with modifiers and locale — the physical key never does.

Hold several keys at once to probe your keyboard's rollover. The “held now” counter shows how many keys register simultaneously; if a key you're physically pressing doesn't light up, your keyboard is ghosting that combination. Once a key registers even once it stays green, so you can methodically confirm every switch on the board, then hit reset to start over.

About the Keyboard Tester

This Keyboard Tester is a free browser tool that lets you confirm every key on your keyboard actually registers. You press keys on your real keyboard and watch the matching key light up on the on-screen layout, turning green the first time it responds. Because it runs entirely in the browser, this online keyboard tester needs no download or install, and it works the same whether you are sitting at a desktop tower, a laptop or a borrowed machine.

The tool is built to surface the problems people care about most: keys that do not respond at all (dead keys), keys that stay active when they should not (stuck keys), and combinations that quietly fail (ghosting). It also lets you probe n-key rollover by holding several keys at once and reading the live count of keys registering simultaneously. For each press you get a readout of the key, the physical code, the legacy keyCode and the key location, so you can see exactly what the browser receives.

How to use the online keyboard tester

Getting a clean result takes about a minute. Follow these steps:

  • Click anywhere on the on-screen keyboard so the tester is focused.
  • Press every key in turn, sweeping across rows so none get skipped.
  • Watch each key turn green once it registers; anything still grey did not respond.
  • Hold several keys together to test rollover and look for ghosting.
  • Use Reset to clear the board and run the check again if needed.

Reading the results is straightforward. A key that lights up and goes green is healthy. A key that never changes color may be faulty, dirty under the cap, or simply intercepted by your browser or operating system. Some keys, such as certain F-keys, the Cmd or Win key, F5 reload or F11 fullscreen, can be captured before the page ever sees them, so test those in a plain text editor before assuming hardware failure.

Using a keyboard tester on Mac, Windows and Chromebook

This keyboard tester website is platform agnostic. As a Mac keyboard tester it reads the same physical key codes Safari, Chrome and Firefox report, so the Command, Option and Control keys map correctly. As a Chromebook keyboard tester it works in the Chrome browser without any extension, which is handy for the lightweight, locked-down machines schools and travelers rely on. On Windows the keyboard tester online behaves identically, mapping by physical position so non-US layouts such as AZERTY or Dvorak still light up the right keys. Whatever the device, the keyboard tester typing flow is the same: focus, press, confirm.

Why a keyboard tester matters

A quick keyboard check saves real frustration. If you are buying a used laptop or a second-hand mechanical keyboard, running this online keyboard tester before you pay is the fastest way to catch dead or sticky switches that a casual glance would miss. Mechanical keyboard owners use it to verify a fresh build, confirm hot-swapped switches seat properly, and measure how many keys their board can report at once. Anyone troubleshooting odd typos, repeated characters or a key that seems to fire on its own can use the live readout to tell a hardware fault from a software quirk.

Because the keyboard tester runs locally and shows results instantly, it is also a reassuring sanity check after spilling liquid, cleaning under keycaps, or plugging in an unfamiliar keyboard. There is nothing to configure and nothing to learn: open the page, click the board, and start pressing keys. In a couple of minutes you will know whether every switch on your keyboard is doing its job, and exactly which ones, if any, need attention.

Frequently asked questions

How do I test if a keyboard key is working?

Open this online keyboard tester, click the on-screen keyboard once to focus it, then press the key you want to check. If the matching key lights up and turns green, it is registering correctly; if it stays grey, the press never reached your computer. Sweep across every row to confirm the whole keyboard in about a minute.

How do I test a keyboard online?

Just start pressing keys with this tester focused and watch the virtual keyboard respond in real time. Each key you press lights up and stays marked as tested, so you can methodically work through letters, numbers, function keys and modifiers without installing anything. It runs in your browser, which makes it the quickest way to check a new, used or repaired keyboard.

Why is one of my keyboard keys not working?

A key that never registers is usually faulty, dirty under the cap, or blocked by debris, but it can also be a software issue such as a remapped layout or a stuck accessibility setting. First confirm the fault in this keyboard tester, then in a plain text editor, since some keys like F5, F11 or the Cmd/Win key are reserved by the browser. If it fails everywhere, the problem is most likely hardware.

How do I fix a keyboard key that is not working?

Start with the simple fixes: power off, turn the keyboard upside down and gently tap it, then clear dust with compressed air. If that does not help, plug in an external keyboard to see whether the issue follows the hardware, and on Windows reinstall the keyboard driver or disable Sticky Keys and Filter Keys. Run this tester after each step to confirm the key now responds.

What is key ghosting?

Ghosting is when you hold several keys at once and some of them silently fail to register, so a keypress you definitely made never reaches the computer. To test it here, hold a few keys together and watch the held now count: if a key you are physically pressing does not light up, your keyboard is ghosting that combination. Inexpensive membrane keyboards ghost most easily, which matters for gaming and fast typing.

What is N-key rollover and anti-ghosting?

N-key rollover (NKRO) is how many keys your keyboard can report at the same time, where full NKRO means every key registers no matter how many you hold; anti-ghosting is the diode design that prevents phantom or missed keys. To gauge yours, mash several real keys together in this tester and read the held-now counter. Most gaming and mechanical keyboards handle many simultaneous keys, while cheaper boards top out around two or six.

How do I test a mechanical keyboard?

Press every switch in this tester and confirm each key turns green, which is the fastest way to verify a fresh build or check that hot-swapped switches seated properly. Then hold clusters of keys to measure rollover and look for any ghosting. Because it reads the physical event.code rather than the character, it works correctly even on custom layouts and remapped boards.

Does this keyboard tester work on Mac and Chromebook?

Yes. This online keyboard tester runs entirely in the browser, so it behaves the same on a Mac, a Chromebook, Windows or Linux with no download or extension. It maps keys by their physical position, so Command, Option, Control and non-US layouts like AZERTY all light up the correct key.

How do I check for a stuck or repeating key?

Press the suspect key once and release it: if it keeps showing as held in the tester after you let go, or a letter repeats on its own in a text box, the switch is physically sticking. This usually points to debris or sticky residue under the cap. On Windows you can also raise the keyboard repeat delay in settings, but a key that sticks mechanically needs cleaning.

Is this keyboard tester free and private?

Yes, it is completely free with no sign-up and no installation. Every keypress is read and shown in your browser only, so nothing you type is logged, stored or uploaded anywhere.

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