function calculate(){
	var bricktype='brit'; var brick16mm=0; var brick25mm=0; var brick50mm=0; var brickplas=0; var brickcorn=0; var brickedge=0; var bricktrim=0;
	var needs16mm=0; var needs25mm=0; var needs50mm=0; var needsplas=0; var needsstra=0; var needsadhe=0; var needsfast=0; var needsmort=0; var needscorn=0; var needsedge=0; var needstrim=0; var needsmtip=0; var needsagun=0; var needsjoin=0;
	
	bricktype=document.forms['brickcalc'].elements["bricktype"].options[document.forms['brickcalc'].elements['bricktype'].selectedIndex].value;
	brick16mm=document.forms['brickcalc'].elements["brick16mm"].value;
	brick25mm=document.forms['brickcalc'].elements["brick25mm"].value;
	brick50mm=document.forms['brickcalc'].elements["brick50mm"].value;
	brickplas=document.forms['brickcalc'].elements["brickplas"].value;
	brickcorn=document.forms['brickcalc'].elements["brickcorn"].value;
	brickedge=document.forms['brickcalc'].elements["brickedge"].value;
	bricktrim=document.forms['brickcalc'].elements["bricktrim"].value;
	
	if ((brick16mm > 0) != true) brick16mm=0;
	if ((brick25mm > 0) != true) brick25mm=0;
	if ((brick50mm > 0) != true) brick50mm=0;
	if ((brickplas > 0) != true) brickplas=0;
	if ((brickcorn > 0) != true) brickcorn=0;
	if ((brickedge > 0) != true) brickedge=0;
	if ((bricktrim > 0) != true) bricktrim=0;
	
	needs16mm=Math.ceil(parseFloat(brick16mm)/2.68);
	needs25mm=Math.ceil(parseFloat(brick25mm)/2.68);
	needs50mm=Math.ceil(parseFloat(brick50mm)/2.68);
	needsplas=Math.ceil(parseFloat(brickplas)/2.68);
	
	var systemSquareM = parseFloat(brick16mm)+parseFloat(brick25mm)+parseFloat(brick50mm)+parseFloat(brickplas);
	
	needsadhe=Math.ceil(parseFloat(systemSquareM)/0.8);
	needsfast=Math.ceil((parseFloat(systemSquareM)*15));
	
	needscorn=Math.ceil(parseFloat(brickcorn)*15/50)*50;
	needsedge=Math.ceil(parseFloat(brickedge)*12/8/24)*24;
	needstrim=Math.ceil(parseFloat(bricktrim)/2.5);
	needsstra=Math.ceil(parseFloat(systemSquareM)*63);
	needssealer = Math.ceil(parseFloat(systemSquareM)/35);
	needsmtip=2;
	needsagun=1;
	needsjoin=1;
	
	if (bricktype=='britannia'){
		needsmort=Math.ceil(parseFloat(systemSquareM)/4);
	}
	
	if (bricktype=='classic'){
		needsmort=Math.ceil(parseFloat(systemSquareM)/2.8);
	}
	
	document.forms['brickcalc'].elements['brick16mm'].value=brick16mm;
	document.forms['brickcalc'].elements['brick25mm'].value=brick25mm;
	document.forms['brickcalc'].elements['brick50mm'].value=brick50mm;
	document.forms['brickcalc'].elements['brickplas'].value=brickplas;
	document.forms['brickcalc'].elements['brickcorn'].value=brickcorn;
	document.forms['brickcalc'].elements['brickedge'].value=brickedge;
	document.forms['brickcalc'].elements['bricktrim'].value=bricktrim;
	document.forms['brickcalc'].elements['needs16mm'].value=needs16mm;
	document.forms['brickcalc'].elements['needs25mm'].value=needs25mm;
	document.forms['brickcalc'].elements['needs50mm'].value=needs50mm;
	document.forms['brickcalc'].elements['needsplas'].value=needsplas;
	document.forms['brickcalc'].elements['needsstra'].value=needsstra;
	document.forms['brickcalc'].elements['needsadhe'].value=needsadhe;
	document.forms['brickcalc'].elements['needsfast'].value=needsfast;
	document.forms['brickcalc'].elements['needsmort'].value=needsmort;
	document.forms['brickcalc'].elements['needscorn'].value=needscorn;
	document.forms['brickcalc'].elements['needsedge'].value=needsedge;
	document.forms['brickcalc'].elements['needstrim'].value=needstrim;
	document.forms['brickcalc'].elements['needsmtip'].value=needsmtip;
	document.forms['brickcalc'].elements['needsagun'].value=needsagun;
	document.forms['brickcalc'].elements['needsjoin'].value=needsjoin;
	document.forms['brickcalc'].elements['needsseal'].value=needssealer;
	
	return true;
}