C Program to Calculate simple interest and total amount

In this section, you will learn how to read the principle, rate and time from the user and write a C program to calculate simple interest and the total amount.


(Here, P = Principal Amount, R= Rate and T= Time)

TOTAL AMOUNT = P + Simple Interest

Logic :

  1. Take input principle amount, time and rate in some variable.
  2. Then take input time in some variable.
  3. Then take input rate in some variable.
  4. Find simple interest using formula mentioned above.
  5. Finally, print the value of Simple Interest.
  6. Then, to find the Total amount add principal amount to the simple interest.

Program to calculate simple interest and total amount

/* C-Program: Calculate Simple Interest and total amount */ 

#include <stdio.h> 

int main() 

long int p; 
int t; 
float r, si, tamt; 

printf("Enter the Principal Amount: "); 
scanf("%ld", &p); 

printf("Enter the Time (or period): "); 
scanf("%d", &t); 
printf("Enter the Rate of Interest: "); 
scanf("%f", &r);

si = (p*t*r)/100;
tamt = p + si; 

printf("\nPrincipal Amount = %ld", p); 
printf("\nTime = %d", t); 
printf("\nRate of interest =%.2f", r);
printf("\nSimple Interest = %.2f", si); 

printf("\nTotal Amount = %.2f", tamt); 

return 0;


Output :-

Enter the Principal Amount:  11200
Enter the Time (or period):  3
Enter the Rate of Interest:  10.5

Principal Amount = 11200
Time             = 3
Rate of interest =10.50
Simple Interest = 3528.00
Total Amount    = 14728.00
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