function calculate() {
var bw = new Array();
bw[0] = 20; bw[1] = 34; bw[2] = 80; bw[3] = 125; bw[4] = 225; bw[5] = 300; bw[6] = 500; bw[7]=700
if (document.calculator.seconds.value == "") document.calculator.seconds.value = 0;
var minutes = eval(document.calculator.minutes.value * 60);
var seconds = eval(document.calculator.seconds.value);
var totaltime = (minutes + seconds);
for (var i=0; i<8; i++) {
var mbsize = 0;
MbSize = eval((totaltime * bw[i]) / 8);
if (MbSize <= 1024) {
	document.calculator[i+2].value = MbSize + " k";
				} 
else if (MbSize > 1024) {
MbSize = MbSize/1024;
var MbSize2 = Math.floor(MbSize);
var tool = Math.round((MbSize*100+.5)%100);
var MbSize3 = tool / 100;
document.calculator[i+2].value = MbSize2 + MbSize3 + " MB";
				}
		}
}