# BMI Calculator in Python – A Complete Step-By-Step Tutorial In this tutorial, we will understand what Body Mass Index or BMI is, how we can create a BMI calculator in the Python programming language.

Let’s get started!

## What is Body Mass Index (BMI)?

`BMI `is dependent on a person’s height and weight. Also, people are classified as being underweight, overweight, or even obese based on their BMI value.

BMI can be used as a substitute for taking precise measurements of body fat percentages. Furthermore, BMI is a low-cost and simple way to check for those who may be at risk of health problems due to their weight.

## BMI Calculator Implementation in Python

BMI is determined by dividing a person’s weight in kilograms twice by their height in meters, Here is the code for the BMI calculator written in Python:

```h=float(input("Enter your height in meters: "))
w=float(input("Enter your Weight in Kg: "))

BMI=w/(h*h)
print("BMI Calculated is:  ",BMI)

if(BMI>0):
if(BMI<=16):
print("You are very underweight")
elif(BMI<=18.5):
print("You are underweight")
elif(BMI<=25):
print("Congrats! You are Healthy")
elif(BMI<=30):
print("You are overweight")
else:
print("You are very overweight")
else:
print("enter valid details")
```

Let us understand the whole code line by line.

`Line 1` and `Line 2` – Taking input for height and weight of the person

Then we check if the BMI is greater than 0 or not as neither the weight nor the height can be negative hence BMI value can never be less than 0.

Now according to the BMI value, the person is categorized into underweight, healthy, and overweight using the if-else conditional statements.