How to Check COM Port in Windows 11

If you work with devices like Arduino boards, serial adapters, or other peripherals that need a COM port, knowing how to check which COM port they’re using in Windows 11 is essential. In this step-by-step guide, we’ll show you multiple ways to find your COM port quickly and accurately.

Table of Contents

What Is a COM Port?

A COM port (short for Communication Port) is a serial interface used by many devices to exchange data with your PC. While most modern devices use USB, many still rely on virtual COM ports for data transfer and debugging.

Why You Might Need to Check COM Ports

Troubleshooting Devices: Find the correct port when a device isn’t detected.
Programming Microcontrollers: Tools like Arduino IDE require the correct COM port to upload code.
Connecting Serial Devices: For CNC machines, modems, or other equipment.

Method 1: Check COM Port via Device Manager

This is the easiest and most reliable way.

Right-click on the Start menu and select Device Manager.
Expand the section Ports (COM & LPT).
Look for your device (e.g., USB Serial Device (COM3)).
Note the COM number next to it — that’s the port your device is using.

Method 2: Use Windows Settings

You can also find COM ports through Settings:

Open Settings (Windows + I).
Go to Bluetooth & devices > Devices.
Scroll down to Related settings and select Device Manager.
Follow the same steps as Method 1.

Method 3: Use Command Prompt

If you prefer using commands:

Press Windows + R, type cmd, and press Enter.
Type the following command:
```
mode
```
Press Enter — you’ll see a list of active COM ports.

Method 4: Use PowerShell

Press Windows + X and select Windows Terminal (Admin).

Type:

Get-WmiObject Win32_SerialPort | Select-Object DeviceID, Name

Press Enter — PowerShell will display all COM ports with names.

Method 5: Check in Arduino IDE (or Similar Software)

If you’re using development software like Arduino:

Open the IDE.
Go to Tools > Port.
You’ll see a list of available COM ports — select the one for your device.

Troubleshooting COM Port Issues

Device Not Showing Up

Try a different USB port.
Reinstall the driver for your device.
Restart your computer.

COM Port Number Conflicts

Open Device Manager.
Right-click your device > Properties > Port Settings > Advanced.
Manually change the COM port number.

Tips for Working with COM Ports

Label Devices: If you work with multiple devices, labeling helps avoid confusion.
Use Powered USB Hubs: They help keep devices stable and prevent disconnects.
Keep Drivers Updated: Prevents compatibility issues.

Conclusion

Checking COM ports on Windows 11 is simple whether you use Device Manager, Command Prompt, or PowerShell. By quickly identifying the correct COM port, you can troubleshoot devices, upload code to microcontrollers, and keep your workflow running smoothly.

FAQs

1. How do I know which COM port my USB device is using?
Check Device Manager under Ports (COM & LPT) — the number next to your device is the COM port.

2. Can I change a COM port number in Windows 11?
Yes, right-click the device in Device Manager, go to Properties > Port Settings > Advanced, and assign a new COM port.

3. Why don’t I see Ports (COM & LPT) in Device Manager?
That means no devices are currently using a COM port — plug one in and refresh.

4. What if my device doesn’t appear at all?
Try reinstalling drivers, using a different cable/port, or restarting your PC.

5. Are COM ports the same as USB ports?
Not exactly — USB devices can create virtual COM ports, but the COM number is a logical assignment, not a physical port.

How to Check COM Port in Windows 11 – A Step-by-Step Guide