I am currently purchasing distressed properties and need to determine if it is feasible to purchase them. Example: I can purchase a house worth 100,000 Dollars pay 115,000 Dollars for it, sell it for 100,000 Dollars and still make a 20,000 Dollar profit. What I am looking for is a formula that will determine the profit margin on each buy. What I am looking for is a Mortgage calculation formula. I cannot seem to find one in any of the books I own. Also what I am looking for is to input the data into boxes, and label each input box, and label each output box, and come up with a graph to show the profit margin, and come up with a formula that will determine how many months to break even.