A Birthday Calendar is a tool used to keep track of the birthdays of friends, family, and colleagues. It can be a physical calendar, a digital app, or an online service that allows users to input and organize important dates. This helps ensure that no special occasion is forgotten and allows for timely celebrations. Many people use a Birthday Calendar to plan gifts, parties, or greetings. Some digital versions can send reminders as the date approaches, making it easier to stay organized. This tool is especially useful for those with large social circles or busy schedules.