A simple date of birth calculator that allows you to find your birthday date by inserting the number of years, number of months and number of days since you born. The tool will automatically update you with your date of birth. It is a fun reverse calculation of age calculator. The birthday date from age calculator will display your date of birth in year-month-date format (yyyy-mm-dd). For example, If I am 20 years 10 months and 14 days old as of August 17,2016 then my DOB would be 3-10-1995.