If you ever needed to access the settings page of your router in order to make some changes to the configuration, then you know that for this you need to know its IP address.
If you forget the IP address, you can determine it using the command in Windows:
Open the Start menu.
Enter cmd in the search.
Right-click on the Command Line application.
Select Run as administrator.
Enter the ipconfig command
After that, you will see the Windows IP Configuration, which has data about your connection. Default Gateway / Main Gateway is the address of your router.