JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" class="ad-title calculate form-control" name="budget" id="budget" value="" placeholder="Enter a daily budget in USD">

<input type="text" class="form-control calculate" id="ppc" name="ppc" value="" placeholder="">
    
    <div id="sum" />

JavaScript

$(document).ready(function() {    
    $(".calculate").bind("keyup change", function(e) {
        var budget = parseFloat($("#budget").val()) || 0;
        var ppc = parseFloat($("#ppc").val()) || 0;
        
        var value = ppc / budget;
        
        if (!isNaN(value) && value !== Infinity) {
            $("#sum").text(value);
        }
    });
});