A date calculator is a tool that helps users perform calculations related to dates. It can determine the difference between two dates, add or subtract days, months, or years, and even find specific days of the week for given dates. These calculators are useful for planning events, tracking deadlines, or simply understanding time intervals. Date calculators can be found in various forms, including online tools, mobile apps, and built-in features in software like spreadsheets. They often allow users to input dates in different formats and provide results quickly, making them convenient for both personal and professional use.