Age calculation is the process of determining a person's age based on their date of birth. To find someone's age, you subtract their birth year from the current year. If their birthday has not yet occurred this year, you also subtract one year from the result. This method provides a straightforward way to understand how old someone is in years. For example, if a person was born on January 15, 2000 and the current date is October 1, 2023, you would calculate their age as follows: 2023 - 2000 = 23. Since January 15 has already passed this year, their age is 23 years.