How to use the Keyboard Tester
- Click anywhere on the page and press each key on your keyboard.
- Keys light up blue while held and stay green once they have registered — any key that stays grey did not reach the computer.
- Hold several keys together to test rollover: “Max at once” shows how many were detected simultaneously.
Find dead, stuck and chattering keys
Press every key once. A key that never turns green is dead (or blocked by the browser — see below). A key that stays blue after you release it is stuck. If the press count jumps by two for a single press, the switch is chattering (double-registering), common on worn mechanical switches.
Rollover and ghosting
Rollover is how many keys a keyboard can register at the same time. Hold several keys — for example W, A, Shift and Space for gaming — and watch “Max at once”. Many office keyboards detect 2–6 keys; gaming keyboards advertise n-key rollover (NKRO). Ghosting is when a key you didn’t press appears or one you did press is ignored because of the keyboard’s wiring matrix.
Key, code and location
For each press the tool shows event.key (the character or name, which depends on your layout), event.code (the physical key position, the same on every layout) and the location (left/right Shift, numpad). Web developers use code for games and shortcuts and key for text.
Keys a browser can’t test
The operating system keeps some keys for itself: the Windows key, Fn, Print Screen on some systems, and shortcuts such as Ctrl+W, Ctrl+T or Cmd+Q. They may not reach the page at all. Media and brightness keys are handled by the system too.
Tools that pair well with the Keyboard Tester
- Click Speed Test (CPS) — How fast can you click?
- Mic Test — Check that your microphone works and sounds right before a call, stream or recording — see the live level, watch the waveform and play back a short test recording.
- Webcam Test — Check that your camera works and looks good before a video call — see the live picture, the real resolution and frame rate, and save a snapshot.
- Dead Pixel Test — Fill your screen with solid colors, gradients and test patterns to spot dead or stuck pixels, backlight bleed and banding — on a new monitor, laptop, TV or phone.