Howdy readers, today you will learn **how to write a program to calculate compound interest using C** Programming language.

**Compound interest** is the interest on a loan or deposit calculated based on both the initial principal and the accumulated interest from previous periods.

The formula to calculate compound interest is:

CI = {p (1 + r/100)^t} - p Where, p = Principal Amount r = Rate of Interest t = Time Period

The below program prompts the user to enter the **principal amount**, **rate of interest** and **time period**. Then, we used the above formula to compute the compound interest.

So, without any delay, letâ€™s begin this tutorial.

**C Program to Calculate Compound Interest**

**C Program**

// C Program to Calculate Compound Interest #include <stdio.h> #include <math.h> int main(){ float p, r, t, CI; // Asking for input printf("Enter the principal amount: "); scanf("%f", &p); printf("Enter the rate of interest: "); scanf("%f", &r); printf("Enter the time period: "); scanf("%f", &t); // Calculating compound interest CI = p * pow((1 + r/100), t) - p; // Displaying result printf("The compound interest is: %.2f", CI); return 0; }

**Output**

Enter the principal amount: 30000 Enter the rate of interest: 3 Enter the time period: 6 The compound interest is: 5821.56

**Explanation**

float p, r, t, CI;

We have declared four float data type variables named **p**, **r**, **t**, and **CI**.

// Asking for input printf("Enter the principal amount: "); scanf("%f", &p); printf("Enter the rate of interest: "); scanf("%f", &r); printf("Enter the time period: "); scanf("%f", &t);

The program prompts the user to enter the principal amount, rate of interest and time period. These values get stored in the **p**, **r**, and **t** named variables respectively.

// Calculating compound interest CI = p * pow((1 + r/100), t) - p;

The compound interest is computed using the formula,

**Compound Interest = [principal * (1 + rate)time] – principal**

The compound interest calculated above gets stored in the **CI** named variable.

// Displaying result printf("The compound interest is: %.2f", CI);

Finally, the compound interest is printed on the screen using **printf()** function. The **%.2f** format specifier is used to limit the result to **2** decimal places.

**Conclusion**

I hope after reading this tutorial, you get to know **how to write a program to calculate compound interest using C** Programming language.

If you have any queries regarding the program, then let us know in the comment section. We will be pleased to solve all of your queries.