# How to calculate area of a circle in Python

In this python tutorial, you will learn about how to calculate area of a circle in Python, you can check the Python program to calculate area of a circle and, also we will check:

• Python program to calculate the area of a circle
• Python program to find the area of a circle using function
• Python program to find the area of a circle using the math module
• Python program to calculate the area and circumference of a circle
• Python program to calculate the area and circumference of a circle using an inbuilt math module
• Python program to find the area and perimeter of a circle
• Python program to calculate the area of a circle using class
• Python program to calculate the area and perimeter of a circle using class

## Python program to calculate area of a circle

Let see python program to calculate the area of a circle.

• Firstly, we will take input from the user using the input() function for radius and store it in a variable.
• We can use constant to store the value of ‘pi’.
• Now, we will calculate the area of a circle by using the formula area = PI * r * r.
• And at last, print the area of a circle to get the output.

Example:

``````PI = 3.14
r = float(input("Enter the radius of a circle:"))
area = PI * r * r
print("Area of a circle = %.2f" %area)``````

You can refer to the below screenshot to see the output for python program to calculate the area of a circle

The above code, we can use to calculate area of a circle in Python.

## Python program to find area of a circle using function

Here, we will see python program to find the area of a circle using function.

• In this example, I have defined a function as def findArea(r).
• We can store the value PI = 3.14 which is fixed.
• The function is returned as return PI * (r * r)
• The function findArea(6) is called and it will print the output.

Example:

``````def findArea(r):
PI = 3.14
return PI * (r*r);
print("Area of circle = %.6f" % findArea(6));``````

You can refer to the below screenshot to see the output for the python program to find the area of a circle using the function. Python program to find the area of a circle using function

The above python code to find area of a circle using function in Python.

## Find area of a circle using Python math module

Now, we will see python program to find area of a circle using the math module.

• In this example, we will import math module which is an inbuilt module.
• We will take the radius as an input from the user.
• Now, we will calculate the area of a circle by using the formula area = math.pi * r * r. The value of “pi” is taken from the “math” module.
• And at last, print the area of a circle to get the output.

Example:

``````import math
r = float(input("Enter the radius of a circle:"))
area = math.pi * r * r
print("Area of a circle = %.2f" %area)``````

You can refer to the below screenshot to see the output for the python program to find the area of a circle using the math module. Python program to find the area of a circle using the math module

The above code, we can use to find area of a circle using Python math module.

## Python program to calculate area and circumference of a circle

Let’s see python program to calculate the area and circumference of a circle.

• Firstly, we will take input from the user using the input() function for radius and store it in a variable.
• We can use constant to store the value of ‘pi’.
• Now, we will calculate the area of a circle by using the formula area = PI * r * r.
• And for calculating the circumference of a circle we will use the formula circumference = 2 * PI * r.
• And at last, print the area and circumference of a circle to get the output. The value is formatted up to two decimal places using %.2f.

Example:

``````PI = 3.14
area = PI * r * r
circumference = 2 * PI * r
print(" Area Of a Circle = %.2f" %area)
print(" Circumference Of a Circle = %.2f" %circumference)``````

You can refer to the below screenshot to see the output for the python program to calculate the area and circumference of a circle. Python program to calculate the area and circumference of a circle

This is the Python program to calculate area and circumference of a circle.

You may like, Python program to find the area of square.

## Python program to calculate the area and circumference of a circle using an inbuilt math module

Here, we will see python program to calculate the area and circumference of a circle using an inbuilt math module.

• Firstly, we will import math module which is an inbuilt module.
• We will take input from the user using the input() function for radius and store it in a variable.
• Now, we will calculate the area of a circle by using the formula area = math.pi * r * r.
• And for calculating the circumference of a circle we will use the formula circumference = 2 * math.pi * r.
• And at last, print the area and circumference of a circle to get the output. The value is formatted up to two decimal places using %.2f.

Example:

``````import math
area = math.pi * r * r
circumference = 2 * math.pi * r
print(" Area Of a Circle = %.2f" %area)
print(" Circumference Of a Circle = %.2f" %circumference)``````

You can refer to the below screenshot to see the output for the python program to calculate the area and circumference of a circle using an inbuilt math module. Python program to calculate the area and circumference of a circle using an inbuilt math module

## Python program to find area and perimeter of a circle

Now, we will see python program to find the area and perimeter of a circle

• Firstly, we will take input from the user using the input() function for radius and store it in a variable.
• We have used 3.14 the value of pi in the formula.
• Now, we will calculate the area of a circle by using the formula area = 3.14* r * r.
• And for calculating the perimeter of a circle we will use the formula perimeter = 2*3.14*r
• And at last, print the area and perimeter of a circle to get the output.

Example:

``````r=float(input("Enter the Radius of circle: "))
area = 3.14*r*r
perimeter = 2*3.14*r
print("Area of Circle: ",area)
print("Perimeter of Circle: ",perimeter)``````

You can refer to the below screenshot to see the output for the python program to find the area and perimeter of a circle. Python program to find the area and perimeter of a circle

The above code, we can use to find area and perimeter of a circle in Python.

## Python program to calculate area of a circle using class

Let see python program to calculate the area of a circle using class.

• In this example, we have created a class named “Circle” and it has an attribute radius as r.
• The constructor of the class initiates the attribute using the __init__function.
• We have used 3.14 the value of pi in the formula.
• The method “area” is created to calculate the area of a given circle.
• An instance of the class “Circle” is created as “obj” and the method is invoked to display the output.

Example:

``````class Circle:
def __init__(self, r):
def area(self):
return 3.14 * (self.radius ** 2)
obj = Circle(8)
print("Area of circle:",obj.area())``````

You can refer to the below screenshot to see the output for the python program to calculate the area of a circle using class. Python program to calculate the area of a circle using class

The above Python code is to calculate area of a circle using class.

## Python program to calculate area and perimeter of a circle using class

Here, we will see python program to calculate the area and perimeter of a circle using class

• In this example, we have created a class named “Circle” and it has an attribute radius as r.
• The constructor of the class initiates the attribute using the __init__function.
• We have used 3.14 the value of pi in the formula.
• The two methods “area” and “perimeter” are created to calculate the area of a given circle.
• An instance of the class “Circle” is created as “obj” and the method is invoked to display the output.

Example:

``````class Circle:
def __init__(self, r):
def area(self):
return 3.14 * (self.radius ** 2)
def perimeter(self):
obj = Circle(3)
print("Area of circle:",obj.area())
print("Perimeter of circle:",obj.perimeter())``````

You can refer to the below screenshot to see the output for the python program to calculate the area and perimeter of a circle using class. Python program to calculate the area and perimeter of a circle using class

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In this Python tutorial, we have learned about the Python programs to calculate the area of a circle. Also, we covered these below topics:

• How to calculate the area of a circle in Python
• How to find the area of a circle using a function in Python
• How to find the area of a circle using the math module in Python.
• How to calculate the area and circumference of a circle in Python.
• Python program to calculate the area and circumference of a circle using an inbuilt math module
• How to find the area and perimeter of a circle in Python
• How to calculate the area of a circle using class in Python
• How to calculate the area and perimeter of a circle using class in Python.