In this article, we will create a simple interest calculator program in java using formula. This program will take all the required values as input from the user and calculate simple interest.

Below is a formula for calculating simple interest

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

Principal is the amount on which interest will be calculated.
Time is the time period in years, for which interest will be calculated.
Rate is the rate of interest in percentage.
In short, it is written as

S.I. = (P * T * R) / 100

Simple interest calculator program
Below is a java program to calculate simple interest based on user input values of principal, rate and time using the above formula.

import java.util.Scanner;

public class SimpleInterestCalculator {

  public static void main(String[] args) throws IOException {
    // create scanner object
    Scanner scanner = new Scanner(;
    // read values
    System.out.println("Enter principal");
    double principal = scanner.nextDouble();
    System.out.println("Enter time in years");
    double time = scanner.nextDouble();
    System.out.println("Enter rate in percent");
    double rate = scanner.nextDouble();
    // calculate simple interest with formula
    double interest = (principal * time * rate)/100;
    System.out.println("Interest is " + interest);

Below is a sample output

Enter principal
Enter time in years
Enter rate in percent
Interest is 200.0

The program reads the required values such as principal, time and rate as user input, applied simple interest formula using these values and prints the result.
User input is read using Scanner class but you can also use other methods to read user input such as BufferedReader class etc.

Hope the article was useful.