Java Calculate Age from LocalDate of Birth

Tags: Java LocalDate DateUtil

In this Java tutorial, we learn how to calculate someone’s age based on their birthday as a LocalDate value in Java programming language.

How to calculate age from LocalDate of birth in Java

A this step, we create a new Java class named DateUtil, in this new class create a new static method named getAge(LocalDate birthday), this method to calculate the number of age from a given LocalDate value and current system date then return age as an integer value.

DateUtil.java 

import java.time.LocalDate;
import java.time.temporal.ChronoUnit;

public class DateUtil {

    /**
     * This method to calculate number of age from given birthday LocalDate value.
     * @param birthday the LocalDate of birth
     * @return number of age
     */
    public static int getAge(LocalDate birthday) {
        LocalDate today = LocalDate.now();
        int age = (int)ChronoUnit.YEARS.between(birthday, today);
        return age;
    }

}

In the following example Java code, we learn how to use the DateUtil class above to calculate age from given LocalDate object in Java program.

GetAgeFromLocalDateExample.java 

import java.time.LocalDate;

public class GetAgeFromLocalDateExample {
    public static void main(String... args) {
        LocalDate birthday = LocalDate.of(1988, 7, 11);

        // Calculate Age from LocalDate of Birth
        int age = DateUtil.getAge(birthday);

        System.out.println("Today: " + LocalDate.now());
        System.out.println("LocalDate of birth: " + birthday);
        System.out.println("Age: " + age);
    }
}
The output as below. 
Today: 2022-08-18
LocalDate of birth: 1988-07-11
Age: 34

Happy Coding 😊

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