Date Calculator API

Professional date calculation API with 6 modular endpoints: add (add time to dates with business day support), subtract (subtract time from dates), difference (calculate differences between dates), age (calculate detailed age with next birthday), format (convert dates to various formats), and business-days (calculate or add business days excluding weekends/holidays). Supports multiple timezones, country-specific holidays (230+ countries), precise breakdowns, and various output formats. Essential for scheduling apps, HR systems, financial applications, and project management tools.