There are more than one billion monthly active users on Instagram, and they all have a unique username dedicated to them. However, if you wish to use some third-party apps that require your Instagram user ID to login, knowing your username won't be enough to let you do the specific tasks. To be able to use these apps, you need to know your Instagram User ID. How will you know your ID if you don't know what it is, and how will it help you? Keep on reading to learn more about the "find Instagram user ID" service.