Keyboard Tester
Press any key. It lights up while held and stays glowing once it has registered. Keys that never light up are not working.
Backlight test: the screen is dark now. Look at your physical keyboard and check that every key lights up evenly with no dead or dim LEDs. Click anywhere to exit.
On a phone or tablet? Connect a Bluetooth or USB keyboard, tap the page once, then press keys. Rotate your phone sideways for bigger keys.
How to find a broken key
Press every key once. If a key does not light up, press it harder and test again. Still dark? The key, its switch or the keyboard connector may be faulty. Browsers cannot read the Fn key and some media keys, so they may not show here. Laptop without a numpad? Untick “Show numpad” and the count adjusts.
Ghosting and rollover test
Hold down several keys at the same time and watch “Pressed now” and “Max at once”. If the number stops rising while you add more keys, your keyboard has hit its limit (many cheap keyboards stop at 6, gaming keyboards often allow 10 or more). Missing presses when you type fast or play games is a sign of ghosting.
Double-typing (chatter) detection
Press each key once, firmly but normally. If a key registers twice almost instantly, it glows red and appears under “Double-press alerts”. A key that does this when you pressed it only once usually has a worn or dirty switch, which is what causes letters to repeat while you type.
What is a keyboard tester?
It's a simple web page that shows which keys your computer is receiving when you press them. Each key you hit lights up on a picture of the keyboard, so you can see right away whether one is dead, stuck or acting strangely. It works with laptop keyboards, desktop keyboards, mechanical boards and external USB or Bluetooth ones.
How to use it
Click anywhere on the page first, so it can pick up your key presses. Then press each key once. It glows while you hold it and stays lit after it registers. Check the "Keys tested" counter at the end, and any key that stayed dark didn't register. You can also hold several keys together to see how many your keyboard can read at once, or tap a key to see whether it types twice. On a laptop with no numpad, untick "Show numpad" and the count adjusts.
When it's worth testing
Before you buy a used laptop, after a spilled drink, when a key feels mushy or types twice, and when you set up a new gaming keyboard. It takes about a minute and saves you guessing which key is the problem.
A key isn't working. Now what?
Start with a restart, and check that Sticky Keys and Filter Keys are off. If the key still won't respond, our guide on fixing keys that stopped working walks through what to try next.
Other free tools
Slow internet getting in the way? Try our Internet Speed Test. It checks your download speed, upload speed and ping in about 20 seconds.
More keyboard guides
Frequently asked questions
Is this keyboard tester free?
Yes. It is completely free, needs no download or sign-up, and works in any modern browser on Windows, macOS, Linux and ChromeOS.
Does the tester record what I type?
No. The test runs entirely in your browser. Your key presses are only used to light up the on-screen keyboard and are never stored or sent anywhere.
Why does the Fn key not show up?
On most laptops the Fn key is handled by the keyboard hardware or firmware and is not passed to the browser, so no website can detect it. The same can apply to some media and brightness keys.
A key does not light up. Is it broken?
Not always. First restart the page and press the key firmly. Then check for Sticky Keys or Filter Keys settings and try cleaning around the key. If it still fails, see our guide on fixing keyboard keys that are not working.
What is the ghosting or rollover test?
Hold several keys down at once and watch the Max at once counter. If it stops rising while you add more keys, your keyboard has reached its limit for simultaneous key presses.
Can this test my laptop's keyboard backlight?
The Backlight test button turns your screen dark so you can look at your physical keyboard and spot dim or dead LEDs. The website cannot control the real lighting itself.