function rnd(x){
	return Math.round(x*100)/100;
}

function calculate(){
	
	var v=115;
	
	var nil=5435; //NI LOWER
	var niu=40040; //NI UPPER
	
	var nila=11; //NI PERCENT AMOUNT
	var niua=1; //NI PERCENT AMOUNT
	
	var tl=36000; //TAX LIMIT
	var pa=5435; //PERSONAL ALLOWANCE
	
	var uta=40; //UPPER TAX PERCENT
	var lta=20; //LOWER TAX PERCENT
	
	s=rnd(document.getElementById("salary").value);
	b=rnd(document.getElementById("bike").value);
	h=rnd(document.getElementById("helmet").value);
	a=rnd(document.getElementById("access").value);
	
	if(isNaN(s)) { s=0; document.getElementById("salary").value=0; }
	if(isNaN(b)) { b=0; document.getElementById("bike").value=0; }
	if(isNaN(h)) { h=0; document.getElementById("helmet").value=0; }
	if(isNaN(a)) { a=0; document.getElementById("access").value=0; }
	
	//TOTAK
	t=b+h+a;
	
	//EX VAT
	ex=(((b+a)/v)*100)+h;

	//NI
	if(s>niu){
		var ni=(ex/100)*niua;
	}else if(s>nil){
		var ni=(ex/100)*nila;
	}else{
		var ni=0;
	}
	
	//INCOMETAX
	if((s-pa)>tl){
		var it=(ex/100)*uta;
	}else if(s>pa){
		var it=(ex/100)*lta;
	}else{
		var it=0;	
	}
	
	//SAVINGS
	var ts=it+ni+(t-ex);
	var tsp=(ts/t)*100
	if(isNaN(tsp)) tsp=0;
	
	//TOTAL NEW COST
	var tc=t-ts;
	var emc=tc/12;
	
	document.getElementById("retail").innerHTML=t;
	document.getElementById("exvat").innerHTML=rnd(ex);
	document.getElementById("mss").innerHTML=rnd(ex/12);
	document.getElementById("it").innerHTML=rnd(it);
	document.getElementById("ni").innerHTML=rnd(ni);
	document.getElementById("ts").innerHTML=rnd(ts);
	document.getElementById("tsp").innerHTML=rnd(tsp);
	document.getElementById("tc").innerHTML=rnd(tc);
	document.getElementById("emc").innerHTML=rnd(emc);
	
}