C Program to Calculate Simple Interest

In this article, we are going to learn how to calculate Simple Interest using a C language program. Simple Interest can be calculated by using a simple formula.

The formula for simple interest is:

Simple Interest = (Principal * Time * Rate of Interest)/100
  • Principal – This is the amount borrowed on interest.
  • Time – This is time for which this money is borrowed.
  • Rate of Interest – This is the rate in % at which interest will be charged.

C Program to Calculate Simple Interest

Now let us see this formula in action using the C program below.

int main()
     float PrincipalAmt, time, rate, SimpleInterest;
     printf("Please enter the Principal Amount: ");
     printf("Please enter the Rate of Interest: ");
     printf("Please enter the Time: ");

     SimpleInterest = ( PrincipalAmt * time * rate ) / 100;

     printf("The Simple Interest due is : %.2f\n",SimpleInterest);

     return 0;


Please enter the Principal Amount: 1200
Please enter the Rate of Interest: 5
Please enter the Time: 6
The Simple Interest due is : 360.00