C Programming Code Examples C > Mathematics Code Examples C Program to Calculate the Simple Interest C Program to Calculate the Simple Interest This C Program calculates the simple interest given the principal amount, rate of interest and time. The formula to calculate the simple interest is: simple_interest = (p * t * r) / 100 where p is principal amount, t is time & r is rate of interest. #include <stdio.h> void main() { float principal_amt, rate, simple_interest; int time; printf("Enter the values of principal_amt, rate and time \n"); scanf("%f %f %d", &principal_amt, &rate, &time); simple_interest = (principal_amt * rate * time) / 100.0; printf("Amount = Rs. %5.2f\n", principal_amt); printf("Rate = Rs. %5.2f%\n", rate); printf("Time = %d years\n", time); printf("Simple interest = %5.2f\n", simple_interest); }