Click Start Testing to begin. While testing, keys will not scroll or act on the page. Working keys turn green.
You know the feeling. A letter goes missing halfway through a sentence, or a key types twice when you only pressed it once, or you've just unboxed a new keyboard and want to know everything works before the return window closes. This tester is built for exactly that. Scroll up, press your keys, and watch which ones light up. It runs in your browser, so there's nothing to download and no account to make.
Below you'll find how the tool works, what it can and can't tell you, and what to try when a key misbehaves.
Quick tip: don't type passwords or anything private while you test. You only need to tap keys, so hit a few at random.
It takes about a minute. No technical know-how needed.
Press the way you normally type. A key that only fails when you hit it quickly or lightly can look perfect if you test it too carefully.
Here's what people usually want to find out when a keyboard starts acting up.
This is the main job. If a key never lights up, you know the problem is real and not just a quirk of one app or document.
Intermittent keys are the annoying ones, because they work just often enough to fool you. Pressing each key several times is the easiest way to catch one that misses now and then.
A key stays green for as long as the browser thinks it's held down. If one stays lit after you let go, it isn't releasing properly, and that's the kind of fault that fills a document with endless repeated letters.
Gamers care about this one. Hold a few keys together and check that they all light up. How many a keyboard can handle at once depends on how it's built, so results differ from model to model.
This tester shows whether a key registers, but it doesn't count how many times. To check for chattering, open our word counter, press the suspect key once, and see if two characters show up. If they do, the switch is probably worn or dirty. You can read more about that further down.
Keep in mind that a browser only sees what your computer hands it. It can't look inside the keyboard, so think of a test result as a strong clue, not a final verdict.
If the test turns up a problem, hold off on buying a new keyboard. A lot of faults are easy to fix. Go through these in order.
For a wired keyboard, unplug it and plug it back in, ideally straight into the computer and not through a hub. For a wireless one, replace or recharge the batteries and check the receiver or Bluetooth pairing.
Switching USB ports sometimes clears up strange behavior. With Bluetooth, remove the keyboard from your device list and pair it again from scratch.
Crumbs, dust and grime cause a lot of sticky or dead keys. Unplug or switch off the keyboard, turn it upside down and give it a gentle shake, then go over it with a soft brush or a little compressed air. Don't push liquid into the keys.
Windows and macOS both have settings that change how a keyboard behaves: language and layout, key repeat rate, and accessibility features like Sticky Keys and Filter Keys. If a key types the wrong character, check the layout first.
Some keyboards have a Function lock, a Windows key lock or a gaming mode that switches certain keys off. Check for a key combo or a small indicator light that shows a mode is active.
Gaming and mechanical keyboards often come with software for lighting, macros and key assignments. Update it, or reset to defaults, to rule out a remapped key.
If the same key fails on a second machine, the keyboard is the problem. If it works fine there, look at the first computer's settings and drivers.
If the fault follows the keyboard everywhere, a switch or the circuitry inside may be worn out. Check the warranty before you buy a new one. Some mechanical keyboards let you swap out individual switches.
A key that doesn't light up isn't always broken. Browsers only get the keys your operating system passes along, and some keys are claimed by the system or the keyboard's own firmware before the page ever sees them. Media keys and the Fn key on most laptops fall into this group.
The Windows key is a special case. This tester can catch it, but only in Chrome or Edge, because it needs fullscreen mode and the browser's keyboard lock feature. That's why the page goes fullscreen when you click Start Testing. In Firefox or Safari the Windows key will probably do its usual thing and open the Start menu.
A few more things to know about the layout:
If you're curious how browsers describe key presses, MDN explains it well in its documentation for the KeyboardEvent interface and its page on the code property. The short version: the page sees what the system sends it, and nothing more.
Different keyboards break in different ways, so it helps to know what you're holding.
These have a rubber layer under the keys. As it wears, keys start to feel mushy or stop responding, usually little by little and in the spots you press most.
Every key has its own switch. They last a long time, but one switch can start double-typing or missing presses, and dust or a spilled drink can cause trouble.
They're thin and tightly packed, and a single failing key is common. Dust under a key or a lifted keycap is often the cause, and a careful clean can fix it.
If your mouse is acting up too, try our mouse tester, or check your clicking speed with the CPS test.
Yes. The tester only listens for which keys you press while the page is open, which is the same thing any website can see when you type on it. Your key presses are handled right in your browser and aren't sent to our servers. It doesn't use your microphone or camera.
The one thing it does ask for is fullscreen mode, which your browser may announce with a short notice. That's how it keeps keys from scrolling or triggering shortcuts while you test. You can leave at any time with the red X, the Stop Testing button, or the Esc key. It's still a good habit not to type anything private into any test page. For the full details on what we collect, see our privacy policy.
Yes. It's free, and you don't need to sign up.
No. It runs in your browser. Open the page, click Start Testing and go.
Yes, it works the same as any other keyboard. Some function and media keys won't show up, because the system handles them itself.
It might be faulty. It might also be a key your system or keyboard software grabs before the browser can see it. Try the key in another app and check your keyboard's settings.
Not really. It needs a physical keyboard, so use a desktop or laptop. If you've connected a Bluetooth keyboard to a tablet, it can work, but a computer is the safer bet.
Yes, as long as it's connected and working. If keys feel slow or drop out, check the battery and the connection first.
You can get a rough idea. Hold several keys together and see whether they all light up. The result depends on your keyboard's design and connection, so check the manufacturer's specs for its real limit.
Usually it's a worn or dirty switch, or a key repeat setting that's too sensitive. Clean the key, check your repeat settings, and use the word counter trick above to test again.
It can show symptoms, like a key that never lights up, but it can't diagnose hardware for certain. If the same fault shows up on more than one computer, the keyboard is the likely culprit.
If your keyboard passes, you might as well test the rest of your gear. Browse the Mech Key Test homepage for our other free tools, count presses with the spacebar counter, or run the webcam test before your next video call.
Ready to see if every key works? Head back to the top of the page and hit Start Testing.