# Java Program to calculate simple interest

March 19, 2022, Learn eTutorial
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To calculate the simple interest in Java. We need the principal amount, interest per year, and time period in a year from the user.

## What is the formula for calculating simple interest?

We can calculate the simple interest by using the formula,

Simple Interest (SI) = (P * R * T )/100

where,

•  P is the Principal amount.
•  R is the Interest rate per Annum.
•  T is the time period in years.

## How to read a float number in java?

For reading a float number from the user, we can use the `nextFloat()` function in the java Scanner class. For reading the float value, we have to write the code as follows:

``````System.out.print("Enter the Principal amount : ");
p = sc.nextFloat();
```
```

## How to implement the java program to calculate simple interest?

First, we have to declare the class SimpleInterest.Then open the main function. Then declare the variables p, r, t, si as `float`. Read the principal amount from the user into the variable 'p'. Read the rate of interest per annum in the variable 'r'. Read the time period in a year from the user into the variable 't'. Then calculate simple interest as 'si = p * n * r / 100'.Then display si using the `system.out.println()` function.

### ALGORITHM

STEP 1: Declare the class SimpleInterest with a public modifier.

STEP 2: Open the `main()` to start the program, Java program execution starts with the `main()`

STEP 3: Declare the variables p, r, t, si as float.

STEP 4: Read the principal amount from the user into the variable p.

STEP 5: Read the rate of interest in the variable r.

STEP 6: Read the time period in the variable t.

STEP 7: Calculate si=p*i*t/100.

STEP 8: Display simple interest as si.

For calculating the SI, we are using the below java concepts, we recommend you to learn those to have a better understanding

## Java Source Code

```                                          ```import java.util.Scanner;
public class SimpleInterest
{
public static void main(String args[])
{
float p, r, t,si;
Scanner sc = new Scanner(System.in);
System.out.print("Enter the Principal amount : ");
p = sc.nextFloat();//Read Principla amount
System.out.print("Enter the Rate of interest per year : ");
r = sc.nextFloat();//Read rate of interset
System.out.print("Enter the Time period in year : ");
t = sc.nextFloat();//Read the time period
sc.close();
si = (p * r * t) / 100;//calculate the simple interest
System.out.print("Simple Interest is: " +si);
}
}```
```

## OUTPUT

```OUTPUT 1

Enter the Principal amount :3000
Enter the Rate of interest per year : 7
Enter the Time period in year : 4
Simple Interest is:840.0

OUTPUT 2

Enter the Principal amount :6000
Enter the Rate of interest per year : 10
Enter the Time period in year : 5
Simple Interest is:3000.0
```

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