How to test your keyboard
- Click on the page. Click anywhere on this page so the browser receives your key presses.
- Press each key. The key turns blue while pressed and green once it has been tested.
- Look for white keys. Keys that stay white didn’t register and may be faulty.
- Test rollover. Hold several keys at once. The “max. keys at once” counter shows how many simultaneous presses your keyboard supports.
Common keyboard problems this test detects
- Dead key: the key never lights up. The switch or membrane may be dirty or damaged.
- Stuck key: the key stays blue after you release it.
- Chattering (double typing): one press appears twice in the history. This is common in worn mechanical switches.
- Ghosting: some keys don’t register when you press several together. Cheap keyboards often support only 2–3 keys at once. Gaming keyboards usually support 6 or more (“N-key rollover”).
Keys that browsers can’t detect
Some keys are handled by your keyboard or operating system and never reach the browser, so no online keyboard test can light them up:
- The Fn key on laptops. Fn combinations do work: press Fn + a key to test the combined function.
- Some media and brightness keys, and combinations reserved by the system, such as Win + L or Ctrl + Alt + Del.
- Print Screen only sends a “key up” event in Windows. It still turns green when you release it.
How to fix a key that doesn’t work
- Clean it: turn the keyboard upside down and shake it, then use compressed air around the key. On mechanical keyboards, remove the keycap and clean underneath.
- Check Fn Lock and Num Lock: if the numpad or F-keys don’t respond as expected, one of these locks may be on.
- Try another USB port or new batteries for wireless keyboards, and re-pair Bluetooth keyboards.
- Reinstall the driver: in Windows Device Manager, uninstall the keyboard and restart. Windows reinstalls it automatically.
Keystrokes are only used to light up the keys on this page. They are not saved or sent anywhere.
Frequently asked questions
Is this keyboard tester safe to use?
Yes. Your key presses are only used to highlight keys on the screen. Nothing you type is logged, stored or sent to any server.
Why doesn’t the Fn key light up?
Fn is processed inside the keyboard itself and never reaches the computer, so no online test can detect it alone. Press Fn together with another key to test the combined function.
What is the difference between ANSI and ISO layouts?
ANSI (US) has a wide horizontal Enter key and a long left Shift. ISO (UK, Europe and Latin America) has a tall Enter key and an extra key next to the left Shift.
Which keys mute me in Zoom, Teams or Google Meet?
Zoom: Alt + A. Teams: Ctrl + Shift + M. Google Meet: Ctrl + D. On a Mac, use ⌘ instead of Ctrl. See all shortcuts in the video call test.
What are event.key, event.code and keyCode?
They are the values a browser reports for each key press. key is the character produced, code is the physical key position and keyCode is an older number code. Developers use them for shortcuts and games.
How do I test N-key rollover (anti-ghosting)?
Hold down as many keys as you can at the same time and watch the “max. keys at once” counter. If it stops at 2–6, your keyboard limits simultaneous key presses.