Java Program to Calculate simple interest and compound interest

Example 1: Calculate Simple Interest in Java

import java.util.Scanner;

class Main {
  public static void main(String[] args) {

    // create an object of Scanner class
    Scanner input = new Scanner(System.in);

    // take input from users
    System.out.print("Enter the principal: ");
    double principal = input.nextDouble();

    System.out.print("Enter the rate: ");
    double rate = input.nextDouble();

    System.out.print("Enter the time: ");
    double time = input.nextDouble();

    double interest = (principal * time * rate) / 100;

    System.out.println("Principal: " + principal);
    System.out.println("Interest Rate: " + rate);
    System.out.println("Time Duration: " + time);
    System.out.println("Simple Interest: " + interest);

    input.close();
  }
}

Output

Enter the principal: 1000
Enter the rate: 8
Enter the time: 2
Principal: 1000.0
Interest Rate: 8.0
Time Duration: 2.0
Simple Interest: 160.0

In the above example, we have used the Scanner class to take principal, rate, and time as input from the user. We then use the formula of simple interest to compute the simple interest.

Simple Interest = (Principal * Rate * Time) / 100

Example 2: Calculate Compound Interest

import java.util.Scanner;

class Main {
  public static void main(String[] args) {

    // create an object of Scanner class
    Scanner input = new Scanner(System.in);

    // take input from users
    System.out.print("Enter the principal: ");
    double principal = input.nextDouble();

    System.out.print("Enter the rate: ");
    double rate = input.nextDouble();

    System.out.print("Enter the time: ");
    double time = input.nextDouble();

    System.out.print("Enter number of times interest is compounded: ");
    int number = input.nextInt();

    double interest = principal * (Math.pow((1 + rate/100), (time * number))) - principal;

    System.out.println("Principal: " + principal);
    System.out.println("Interest Rate: " + rate);
    System.out.println("Time Duration: " + time);
    System.out.println("Number of Time interest Compounded: " + number);
    System.out.println("Compound Interest: " + interest);

    input.close();
  }
}

Output

Enter the principal: 1000
Enter the rate: 10
Enter the time: 3
Enter number of times interest is compounded: 1
Principal: 1000.0
Interest Rate: 10.0
Time Duration: 3.0
Number of Time interest Compounded: 1
Compound Interest: 331.00000000000045

In the above example, we have used the formula of compound interest to calculate the compound interest.

Here, we have used the Math.pow() method to calculate the power of the number.