Create an EMI Calculator Plugin in WordPress

Creating a WordPress plugin to add an EMI calculator to your website involves several steps. You’ll need to use PHP to create the plugin itself and JavaScript to handle the calculations.

Here’s a general outline of the steps you would need to take to create an EMI calculator plugin for WordPress:

1. Create a new folder for your plugin in the wp-content/plugins directory of your WordPress installation. Give the folder a unique name, such as wp-emi-calculator.

2. In the plugin folder, create a new file named emi-calculator.php and add the following code at the top of the file to define your plugin’s headers:

<?php
/*
Plugin Name: EMI Calculator
Plugin URI: http://yourwebsite.com/emi-calculator
Description: A simple EMI Calculator for WordPress
Version: 1.0
Author: Your Name
Author URI: http://yourwebsite.com
*/

3. Create a new folder named js within the plugin folder, and create a new file named emi-calculator.js. Add JavaScript code to handle the EMI calculations.

function calculateEMI(loanAmount, interestRate, loanTerm) {
  var interest = (interestRate/100) / 12;
  var emi = (loanAmount * interest * Math.pow(1 + interest, loanTerm)) / (Math.pow(1 + interest, loanTerm) - 1);
  return emi;
}

4. In the plugin’s PHP file, enqueue the javascript file created in the previous step

function emi_calculator_scripts(){
    wp_enqueue_script( 'emi-calculator', plugin_dir_url( __FILE__ ) . 'js/emi-calculator.js', array( 'jquery' ), '1.0.0', true );
}
add_action( 'wp_enqueue_scripts', 'emi_calculator_scripts' );

5. Create the HTML form for the EMI calculator in the plugin’s PHP file.

function emi_calculator_form() {
    echo '<form>';
    echo '<label>Loan Amount:</label>';
    echo '<input type="text" id="loanAmount">';
    echo '<br>';
    echo '<label>Interest Rate:</label>';
    echo '<input type="text" id="interestRate">';
    echo '<br>';
    echo '<label>Loan Term (in months):</label>';
    echo '<input type="text" id="loanTerm">';
    echo '<br>';
    echo '<button type="button" onclick="calculateEMI()">Calculate EMI</button>';
    echo '</form>';
}

6. Add a shortcode or a widget for the EMI calculator form created in the previous step so that it can be placed anywhere in the pages or widgets.

// Add the shortcode for the EMI calculator
add_shortcode( 'emi_calculator', 'emi_calculator_shortcode' );

// Function to display the EMI calculator form
function emi_calculator_form() {
    echo '<form>';
    echo '<label>Loan Amount:</label>';
    echo '<input type="text" id="loanAmount">';
    echo '<br>';
    echo '<label>Interest Rate:</label>';
    echo '<input type="text" id="interestRate">';
    echo '<br>';
    echo '<label>Loan Term (in months):</label>';
    echo '<input type="text" id="loanTerm">';
    echo '<br>';
    echo '<button type="button" onclick="calculateEMI()">Calculate EMI</button>';
    echo '<br>';
    echo '<label>EMI:</label>';
    echo '<span id="emiResult"></span>';
    echo '</form>';

    echo '<script type="text/javascript">
            function calculateEMI() {
                var loanAmount = document.getElementById("loanAmount").value;
                var interestRate = document.getElementById("interestRate").value;
                var loanTerm = document.getElementById("loanTerm").value;

                var interest = (interestRate/100) / 12;
                var emi = (loanAmount * interest * Math.pow(1 + interest, loanTerm)) / (Math.pow(1 + interest, loanTerm) - 1);
                document.getElementById("emiResult").innerHTML = emi.toFixed(2);
            }
          </script>';
}

// Function to return the EMI calculator form
function emi_calculator_shortcode() {
    ob_start();
    emi_calculator_form();
    return ob_get_clean();
}

This plugin will create a shortcode [emi_calculator] that can be placed anywhere in the pages or widgets. When the user enters the loan amount, interest rate, and loan term and clicks the “Calculate EMI” button, the JavaScript function calculateEMI() will be called to calculate the EMI, and the result will be displayed on the page.

Please keep in mind, This is a basic example of how to create an EMI calculator plugin for WordPress, You can add more functionality, validation, error handling, and customization as per your requirement.