Calculating group expenses has always been a headache. It is usually tracked by either writing on a white board with a erasible marker, or keeping track on an excel sheet. These two methods are limited and are not efficient for group book-keeping. The problem with the white board is that you and your friends have to do all the calculation at the end of the month. The problem with Excel sheet is that one person does all the tracking, and is usually saved on one computer. So CostShare.net was born. CostShare.net provides real time calculation, expense tracking by all parties, email notifications, and is accessible on any computer with an internet connection.