# Implementing an Interactive BMI Calculator Using HTML Code for Your Website

HTML calculation Javascript calculation BMI calculator code

Body Mass Index (BMI) is a measure of body fat based on height and weight that applies to both adult men and women. BMI is a commonly used measure to determine if someone is underweight, normal weight, overweight, or obese. BMI is easy to calculate and can provide a general idea of a person’s health status. BMI calculators are widely available on the internet and can be used to quickly and easily calculate one’s BMI. In this article, we will discuss how to create a BMI calculator for a website using HTML code.

## BMI Formula

Before we dive into creating a BMI calculator, it’s important to understand the formula used to calculate BMI. The formula is:

``````BMI = weight(kg) / (height(m) x height(m))
``````

Where weight is in kilograms and height is in meters.

## Creating a BMI Calculator

To create a BMI calculator, we will need to create an HTML form that collects the user’s weight and height information, and then calculates the BMI using the formula above.

### Step 1: Create the HTML form

The first step is to create the HTML form that collects the user’s weight and height information. The HTML form will include two input fields for weight and height, as well as a button to calculate the BMI.

``````
<div class="container mt-5">
<form>
<div class="mb-3">
<label for="weight">Weight (kg):</label>
<input type="number" value="80" id="weight" name="weight" required>
</div>

<div class="mb-3">
<label for="height">Height (cm):</label>
<input type="number" value="170" id="height" name="height" required>
</div>

<div>
BMI: <span r-calc="weight / ((height/100) * (height/100))"> </span>
</div>

</form>
</div>
``````

In this code, we have created two input fields for weight and height, each with a unique ID and name attribute. We have also added a label for each input field to make it clear what information the user needs to enter.

### NittiJS to do the calculation

NittiJS makes it so much easier to do the calculation. Just provide the formula in the `r-calc` attribute. The calculation is done every time you change the height or weight.

### Demo

See the Pen Calculate age HTML Code (Using NittiJS)