Calculators
Age Calculator

Purpose

The Age Calculator can determine the age or interval between two dates. The calculated age will be displayed in years, months, weeks, days, hours, minutes, and seconds.

Age Calculator explained

Age can be calculated differently depending on cultural conventions. This calculator follows the most widely used system, in which a person’s age increases on their birthday. Under this approach, someone who has lived for 3 years and 11 months is considered 3 years old and will turn 4 on their next birthday, one month later. This is the standard method in most Western countries.

In other traditions, age may be counted by including the current year of life. For instance, a person described as twenty years old may also be referred to as being in their twenty-first year. In a traditional Chinese system, individuals are considered one year old at birth, and their age increases at the time of the Traditional Chinese New Year rather than on their birthday. As an illustration, a baby born one day before the Traditional Chinese New Year would be considered two years old just two days later, despite being only two days old chronologically.

Age calculations expressed in months and days can also create ambiguity, particularly when the starting date falls at the end of a month. For example, February 20 to March 20 is typically counted as one month. However, the period from February 28, 2022 to March 31, 2022 can be interpreted in two reasonable ways. If February 28 to March 28 is treated as one month, the result is one month and three days. Alternatively, if both February 28 and March 31 are regarded as end-of-month dates, the result may be considered exactly one month. Similar issues arise with date ranges such as April 30 to May 31 or May 30 to June 30. These discrepancies stem from the unequal number of days in calendar months. This calculator applies the first method in such cases.