Creating a BMI Calculator in Java

How to Create a BMI Calculator in Java

Body mass index, or BMI for short, is a measure of body fat based on height and weight. It’s used to evaluate the health of an individual and can help to determine the risk of developing health-related problems. In this tutorial, we’ll show you how to calculate your BMI using Java.

Getting Started

To start, create a new Java application and ensure that you have the necessary javax.swing library imported into your project (it may already be imported depending on how you set up your project). You’ll also need two text boxes, labels, and a button.

Creating the Application

Once you have all of your components set up, we’re ready to write the code to compute the BMI. The following code simply takes the input from the two text boxes and calculates the BMI:

double height = Double.parseDouble(txtHeight.getText());
double weight = Double.parseDouble(txtWeight.getText());
 
double bmi = weight / (height * height);
 
lblResult.setText("Your BMI is " + bmi);

Now that we have our code written, let’s take a look at what happens when the button is clicked. We’ll create an action listener for the button and add the necessary code to it:

btnCalculate.addActionListener(new ActionListener(){ 
  public void actionPerformed(ActionEvent e){ 
    double height = Double.parseDouble(txtHeight.getText());
    double weight = Double.parseDouble(txtWeight.getText());
 
    double bmi = weight / (height * height);
 
    lblResult.setText("Your BMI is " + bmi);
} 
}); 

That’s all there is to it! Now when you run your application, typing in your height and weight will calculate your BMI.

Conclusion

In this tutorial we showed you how to create a BMI calculator in Java. We walked through the necessary components, wrote the code to compute the BMI, and finally created an action listener for the button. With these steps, you can easily create a BMI calculator in Java.