Age Difference Calculator

The calculator first identifies which of the two dates is earlier (Person A or B) and assigns it as the 'older' date. It then computes the difference in three steps. First, it subtracts the years. Second, it subtracts the months; if the result is negative, one year is borrowed and 12 months are added. Third, it subtracts the days; if the result is negative, it borrows from the previous month by using that month's actual day count (accounting for leap years). This approach correctly handles edge cases like comparing January 31 to March 1 or dates that span a February 29. For the total day count, all dates are converted to UTC midnight timestamps and the difference in milliseconds is divided by 86,400,000 to avoid any daylight saving time ambiguity. The result is always a non-negative integer representing the precise number of calendar days between the two birth dates.