## Python Programming Examples Tutorial Index

This Python program calculates Body Mass Index (BMI); it uses a simple formula to measure the amount of body fat based on a person's weight and height.

### Python Program to Calculate BMI

Example:

This Python program asks for user inputs, validates them, and performs simple calculations via a formula to obtain the BMI index.

``````while True:
try:
# Taking user input
except ValueError:
# Validation error.
else:
if Height <= 0 or Weight <= 0:
print("Your input must not be zero or less.")
continue
else:
# Calculate BMI
BMIIndex = round(Weight / (Height * Height) * 703, 2)

# Print the output
print("Your Body Mass Index is: ", BMIIndex)

if BMIIndex < 18.5:
print("Underweight.")
elif BMIIndex <= 24.9:
print("Normal.")
elif BMIIndex <= 29.9:
print("Overweight.")
else:
print("Obese.")
break``````

Output:

```Please enter your height in inches: 72
Your Body Mass Index is:  24.55
Normal.```

## What Is Body Mass Index (BMI)

Body mass index is called BMI, which measures the amount of body fat based on a person's weight and height. As per the WHO (World Health Organization), The standard BMI value is 18.5 to 24.9; If BMI falls in this range, a person's body height and weight ratio are considered healthy. A BMI less than 18.5 indicates a very skinny and underweight person who needs to increase their calorie and carbohydrate content. A BMI greater than 25 to 29.9 indicates that the person is overweight. A BMI above the range of 30 is considered very dangerous. And such a person can be classified as obese.

### BMI Formulas

This Python program uses the formula below to calculate the BMI:

`BMI = [weight (pound) / height2 (inches) ]* 703`

Example:

For example, a person's weight is 181 lbs, and his height is 72 inches. So let's know what his BMI is?

```Height: 72 inches
Square of height: (72 * 72), m2 = 5182
Weight: 181 lbs
BMI = 181/5182*703 = 24.55```
##### Python Syntax:
`print(round(Weight/(Height*Height)* 703,2));`

This BMI calculator is not clinical guidance nor a substitute for professional medical advice. Since BMI depends on weight and height, it is only an indicator of body obesity. The amount of fat in individuals with the same BMI may vary. Individuals may consider seeking advice from their healthcare providers.