JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<div class="prod-row-wrap">
 <div class="prod-new-row">
  <div class="prod-name">
								 <select class="form-control" name="prod_name[]">
									 <option value="x">Platinum subscription</option>
									</select>
								</div>
								<div class="prod-quan">
									<input type="text" name="quantity" class="form-control" />
								</div>
								<div class="prod-price">
								 <input type="text" name="price" class="form-control" />
								</div>
								<div class="prod-tax">
								<input type="text" name="tax" class="form-control" />
								</div>
								<div class="prod-total">
								 <p>&pound; <span class="total">0</span></p>
								</div>
								<div class="prod-delete">
								 <a href="#" class="remove_field">Remove</a>
								</div>
							</div>
								<button class="btn btn-lg add_product_button">Add product</button>
                </div>

JavaScript

$('[name="tax"]').on('input', function() {
 var quantity = $('[name="quantity"]').val();
 var price = $('[name="price"]').val();
 var tax = $('[name="tax"]').val();
 var subtotal = quantity * price;
 var tax_total = (subtotal / 100) * tax;
 var total = subtotal + tax_total;
 $('.total').text(total);
});













var prod_wrapper = $('.prod-row-wrap');
 var prod_add_button = $(".add_product_button");
 $(prod_add_button).click(function(e){
  e.preventDefault();
   $('<div class="prod-new-row"><div class="prod-name"><select class="form-control" name="prod_name[]"><option value="x">Platinum subscription</option></select></div><div class="prod-quan"><input type="text" name="quantity[]" class="form-control" /></div><div class="prod-price"><input type="text" name="name[]" class="form-control" /></div><div class="prod-tax"><input type="text" name="name[]" class="form-control" /></div><div class="prod-total"><p>&pound;0</p></div><div class="prod-delete"><a href="#" class="remove_field">Remove</a></div></div>').insertBefore(prod_add_button);
 });
 $(prod_wrapper).on("click",".remove_field", function(e){
  e.preventDefault();
		$(this).closest('div.prod-new-row').remove();
 });