function calculateTotals(numPacks) {

	if (!isNaN(numPacks)) {
		if (numPacks > 15 || numPacks < 1) {
			alert('Please enter a number between 1 - 15');
		}
		else {
			// Cost
			var costWeek = numPacks * 7 * 7;
			var costYear = costWeek * 52;
			
			// Time
			var timePerDay = (numPacks * 23 * 5) / 60;
			var timePerWeek = timePerDay * 7;
			var timePerYear = timePerWeek * 52;
			
			//Tar
			var tarPerTenYear = numPacks * 5;
			var tarPerYear = tarPerTenYear / 10;
	
			document.getElementById('costWeek').innerHTML  = '$' + costWeek.toFixed(2);
			document.getElementById('costYear').innerHTML  = '$' + costYear.toFixed(2);
			
			document.getElementById('timePerWeek').innerHTML  = timePerWeek.toFixed(0) + ' hours';
			document.getElementById('timePerYear').innerHTML  = timePerYear.toFixed(0) + ' hours';
			
			document.getElementById('tarPerYear').innerHTML  = tarPerYear.toFixed(0) + ' litres';
			document.getElementById('tarPerTenYear').innerHTML  = tarPerTenYear.toFixed(0) + ' litres';
			
			var packsText = '<span style="font-size: 24px; font-weight: bold;">' + numPacks + '</span><br />Packs Per Day';
			document.getElementById('packsText1').innerHTML =  packsText;
			document.getElementById('packsText2').innerHTML =  packsText;
			document.getElementById('packsText3').innerHTML =  packsText;
		}
	}
	else {
		alert('Please enter how many packs you smoke per day.');
		document.getElementById('numPacks').focus();
	}
}