# C Program to Calculate Simple Interest

C program to calculate simple interest; Through this tutorial, you will learn how to calculate simple interest in c program with the help of function, and normal formula.

## Programs to Calculate Simple Interest in C

Let’s use the following algorithm to write a program to calculate simple interest (i = (prn)/100 ) in c:

• Algorithm to Calculate Simple Interest
• C Program to Calculate Simple Interest using Formula
• C Program to Calculate Simple Interest using Function

### Algorithm to Calculate Simple Interest

Use the following algorithm to write a program to calculate simple interest; as follows:

• Get input principle amount and store in some variable.
• Get input time and store in some variable..
• Get input rate and store in some variable..
• To calculate simple interest using formula `SI = (principle * time * rate) / 100`.
• Finally, print the result of simple interest.

### C Program to Calculate Simple Interest using Formula

```/**
* C program to calculate simple interest
*/

#include <stdio.h>

int main()
{
float principle, time, rate, SI;

/* Input principle, rate and time */
printf("Enter principle (amount): ");
scanf("%f", &principle);

printf("Enter time: ");
scanf("%f", &time);

printf("Enter rate: ");
scanf("%f", &rate);

/* Calculate simple interest */
SI = (principle * time * rate) / 100;

/* Print the resultant value of SI */
printf("Simple Interest = %f", SI);

return 0;
}
```

The output of the above c program; as follows:

```Enter principle (amount): 10000
Enter time: 1.5
Enter rate: 5
Simple Interest = 750.000000```

### C Program to Calculate Simple Interest using Function

```/**
* C program to calculate simple interest
*/

#include <stdio.h>

// function for finding simple interest
float SimpleInt(float p, float r, float t)
{
float si;
si = (p * r * t)/100; // formula
return si; // returning yhe value of si
}

int main()
{
float principle, time, rate, SI;

/* Input principle, rate and time */
printf("Enter principle (amount): ");
scanf("%f", &principle);

printf("Enter time: ");
scanf("%f", &time);

printf("Enter rate: ");
scanf("%f", &rate);

/* Call function with paramters to Calculate simple interest */
SI = SimpleInt(principle, rate, time);

/* Print the resultant value of SI */
printf("Simple Interest = %f", SI);

return 0;
}
```

The output of the above c program; as follows:

```Enter principle (amount): 20000
Enter time: 2
Enter rate: 5
Simple Interest = 2000.000000```