Operating Expense Margin Formula is a concept used to measure the profitability of a business by indicating the proportion of money left after all expenses have been paid out. It tells you how much money is available to reinvest in the company. The formula for calculatingOperating Expense Margin is: Net Operating Profit/Total Revenue x 100. This shows the percentage of revenue left over after accounting for all operating expenses such as wages, raw materials, utilities, and depreciation. By understanding the Operating Expense Margin Formula, businesses can better plan their budgeting and make informed decisions about where to invest resources in order to maximize profits.