JSFiddle - React, Tailwind, and code Playground

HTML

<div class="calculator">
<form action="#" name="ratescalc">
	<div class="calculator__inputs">
		<div class="calculator__inputs__item">
			<div class="calculator__inputs__label">
				<label for="Purprice">Purchase Price or Mortgage Amount</label>
				<input type="text" id="Purprice" name="Purprice" placeholder="Enter price..">
			</div>
		</div>
		<div class="calculator__inputs__item">
			<div class="calculator__inputs__label">
				<label for="PCCost">Premium, Stamps or Tax</label>
				<input type="text" id="PCCost" name="PCCost" value="0.00">
			</div>
		</div>
	</div>
	<div class="calculator__buttons">
		<button data-but="insurance-premium">Title Insurance Premium</button>
		<button data-but="florida-stamps-deed">Florida Documentary Stamps on Deed</button>
		<button data-but="florida-stamps-mortgage">Florida Documentary Stamps on Mortgage</button>
		<button data-but="florida-stamps-deed-single">Dade - Documentary Stamps on Deed (single family)</button>
		<button data-but="florida-intangible">Florida Intangible Tax on Mortgage</button>
		<button data-but="dade-surtax">Dade - Documentary Stamps & Surtax on Deed (non-single family)</button>
    </div>
</form>
</div>

CSS

* {
	margin: 0;
	padding: 0;
	list-style: none;
	box-sizing: border-box;
}

body {
	font-family: Tahoma, sans-serif;
	font-size: 14px;
	padding-top: 100px;
}

.wrap {
	width: 960px;
	margin: 0 auto;
}

.calculator {
	background: #F0F0F0;
	padding: 20px 20px 5px;
}

.calculator__inputs__item {
	width: 49%;
	margin-right: 2%;
}

.calculator__inputs__item:last-child { margin: 0; }

.calculator__inputs {
	display: flex;
	margin-bottom: 15px;
}

.calculator__inputs__label {
	display: flex;
	flex-direction: column;
}

.calculator__inputs__label label {
	margin-bottom: 8px;
}

.calculator__inputs__label input[type="text"], #selectService {
	width: 100%;
	padding: 10px 15px;
	font-size: 18px;
}

.calculator__buttons {
	display: flex;
	flex-wrap: wrap;
	justify-content: space-between;
}

.calculator__buttons button, #doit {
	width: 32%;
	margin: 0 0 15px 0;
	outline: none;
	border: none;
	display: inline-block;
	cursor: pointer;
	font-weight: 700;
    font-family: "Helvetica Neue",HelveticaNeue,Helvetica,Arial,sans-serif;
	background: #23b533;
    font-size: 13px;
    padding: 10px 15px;
    border-radius: 3px;
    text-transform: uppercase;
    color: #fff;
}

#doit {
	width: auto;
	margin-top: 20px;
}

.calculator__buttons button:hover {
	background: #2ECC40;
}

JavaScript

$(".calculator__buttons button").on('click', function(){
  
	var dataButton = $(this).data('but');
  
	switch(dataButton) {
		case 'insurance-premium':
			calcFLInsurPremium(document.ratescalc.Purprice, document.ratescalc.PCCost);
			return false;
			break;
		case 'florida-stamps-deed':
			calcFLTaxOnMortgage(document.ratescalc.Purprice, 1, document.ratescalc.PCCost);
			return false;
			break;
		case 'florida-stamps-deed-single':
			calcFLTaxOnMortgage(document.ratescalc.Purprice, 4, document.ratescalc.PCCost);
			return false;
			break;
		case 'florida-stamps-mortgage':
			calcFLTaxOnMortgage(document.ratescalc.Purprice, 2, document.ratescalc.PCCost);
			return false;
			break;
		case 'florida-intangible':
			calcFLTaxOnMortgage(document.ratescalc.Purprice, 3, document.ratescalc.PCCost);
			return false;
			break;
		case 'dade-surtax':
			calcFLTaxOnMortgage(document.ratescalc.Purprice, 5, document.ratescalc.PCCost);
			return false;
			break;
	}
});

		var MAX_MORTGAGE_DIGITS					= 30
		var TX_TYPE_DOC_STAMP_ON_DEED			= 1
		var TX_TYPE_DOC_STAMP_ON_MORTGAGE		= 2
		var TX_TYPE_INTANGIBLE_TAX				= 3
		// dade county documentary stamp on single family home
		var TX_TYPE_DADE_SINGL_DSTAMP_ON_DEED = 4		
		// dade county documentary stamp on non-single family home
		var TX_TYPE_DADE_NONSINGL_DSTAMP_ON_DEED = 5
		var FL_INTANGIBLE_TAX_MULTIPLIER	= 0.002
		var FL_DOC_STAMP_ON_MORT_MULTIPLIER = 0.35
		var FL_DOC_STAMP_ON_DEED_MULTIPLIER = 0.70
		// multiplier for dade county documentary stamp on single family home
		var DADE_FL_SINGL_DSTAMP_ON_DEED_MULTIPLIER = 0.60
		// multiplier for dade county documentary stamp on non-single family home
		var DADE_FL_NONSINGL_DSTAMP_ON_DEED_MULTIPLIER = 1.05
		var FL_DOC_STAMP_MORT_PER_VALUE		= 100.00
		var FL_DOC_STAMP_DEED_PER_VALUE		= 100.00
		var ONE_HUNDRED_THOUSAND			= 100000.00
		var ONE_MILLION						= 1000000.00
		var FIVE_MILLION					= 5000000.00
		var TEN_MILLION						= 10000000.00
		var FL_UPTO_100K_MULTIPLIER			=...