Age Calculator Calculator is a tool that allows users to calculate their age in years, months, and days. It is especially helpful for those who need to know their age for legal or medical purposes. To use the Age Calculator, users enter their birthdate and the calculator will calculate their age in years, months, and days. The calculator can also calculate the age difference between two people, or between two dates. For example, if two people were born on the same day in different years, the Age Calculator would be able to tell how many years, months, and days apart they are. Age Calculator can also be used to calculate the age of someone based on their date of death.