Use our years between dates calculator to find the number of years between any two dates. Plus, learn how to find the difference in years . This free age calculator computes age in terms of years , months, weeks, days, hours, minutes, and seconds, given a date of birth. The Date Calculator is a simple tool that will help you with date computations with its three (3) functionalities - add, subtract and get the date duration between two dates. You can add 1 year and 3 months or you can subtract 120 days from a starting date. Find the number of years , months, weeks, and days between dates. Click "Settings" to define holidays. The Gregorian calendar is the most prevalently used calendar today. Within this calendar, a standard year consists of 365 days with a leap day being introduced to the month of February during a leap year.