Keyboard Test
Online Key & Ghosting Checker
Check your mechanical or membrane keyboard keys online. Our interactive virtual layout tracks modifier keys, measures input response times, and identifies ghosting blocks.
Modifier keys Shift, Ctrl, and Alt will light up in active cyan when pressed down.
What Is the Keyboard Test?
The Keyboard Test is a dedicated online utility designed to measure, evaluate, and track a user's keyboard input functionality and switch responsiveness. An online keyboard tester plays a crucial role in verifying that every switch registers correctly, identifying stuck or unresponsive keys, and checking modifiers and keystroke combinations under real-world workloads.
Unlike basic input trackers, our Keyboard Test uses an advanced event tracking algorithm that captures inputs on the microsecond scale. As you press keys on your physical layout, our virtual keyboard matrix lights up to provide immediate visual feedback. Pressing keys highlights them in cyan, and releasing them leaves a steady green border to confirm they have been registered at least once during your diagnostic session.
Held Keys State: Highlighted in active cyan
Registered Keys State: Confirmed with a steady green border
NKRO Verification: Monitors peak simultaneous key combinations
📋 Key Registration
Our tool monitors keydown and keyup events globally, mapping inputs to a responsive layout to help you identify dead or sticky switches.
⚡ Modifier Combinations
Check the operation of Shift, Control, Alt, and OS/Command keys to ensure complex software and gaming shortcuts function correctly.
⏱️ Ghosting & NKRO
Verify your keyboard's rollover limits and test for ghosting blocks when pressing multiple keys simultaneously.
🔧 Hardware Diagnostics
Verify layouts after repairs, check Bluetooth connectivity, and confirm that your key switches register cleanly without repeat errors.
N-Key Rollover (NKRO) vs. 6-Key Rollover (6KRO)
A key performance metric for mechanical keyboards is **Key Rollover**, which determines how many simultaneous key presses your hardware can register.
Standard mechanical keyboards often feature 6-Key Rollover (6KRO), meaning the hardware can process up to six alphanumeric inputs along with modifier keys at the same time. High-performance gaming keyboards incorporate N-Key Rollover (NKRO), which utilizes individual diodes at each switch contact. This matrix circuitry allows the controller to scan and register every single key pressed simultaneously, completely eliminating ghosting blocks.
6-Key Rollover (6KRO)
Standard for typical office keyboards. Supports up to six simultaneous alphanumeric inputs along with modifier keys, which is suitable for standard typing tasks.
N-Key Rollover (NKRO)
Essential for gaming and fast typing. Uses individual diodes at each switch to allow every key pressed to register simultaneously, completely eliminating input blocking.
Keyboard Ghosting
Occurs when pressing multiple keys on a standard keyboard causes an additional, unpressed key to register. Most keyboards use blocking to prevent this, which can cause some keys to be ignored instead.
Understanding Key Chatter and Debounce Times
Mechanical key switches rely on physical metal contacts that vibrate or bounce when pressed. This vibration can cause the keyboard controller to register multiple rapid inputs from a single physical press, a problem known as **key chatter**.
To prevent key chatter, manufacturers implement a software filter called **debounce delay**. This filter ignores additional inputs for a short window (typically 5ms to 15ms) after a key is pressed. Lowering this delay in keyboard software can make the keys feel more responsive, but setting it too low can result in accidental double-typing issues.
Linear Switches
Linear switches (such as Cherry MX Red) have a smooth, quiet key travel with no tactile bump, offering fast registration and light actuation force.
Tactile Switches
Tactile switches (such as Cherry MX Brown) feature a light bump halfway through the key travel, providing tactile feedback without a loud click sound.
Clicky Switches
Clicky switches (such as Cherry MX Blue) offer both a tactile bump and a distinct click sound on activation, preferred by typists for clean, audible feedback.
Keyboard Layout Key Mappings
When you press keys on your keyboard, the browser translates those physical inputs into digital event properties. Use this table as a reference for standard keyboard event properties:
| Event Code | Standard Key Character | macOS Equivalent | Common Use Case |
|---|---|---|---|
| ShiftLeft / ShiftRight | Shift | ⇧ Shift | Enables uppercase letters or alternate symbols |
| ControlLeft / ControlRight | Ctrl | ⌃ Control | Standard system shortcut modifier |
| AltLeft / AltRight | Alt | ⌥ Option | Alternate key functions or special character inputs |
| MetaLeft / MetaRight | Windows | ⌘ Command | OS menu navigation or application shortcuts |
| Enter | Enter | ↩ Return | Confirm actions, insert line breaks, or send messages |
This tool monitors globally dispatched keyboard events, using the standard e.code property to highlight corresponding keys on our virtual layout: