In business, operating margin—also known as operating income margin, operating profit margin, EBIT margin and return on sales (ROS)—is the ratio of operating income ("operating profit" in the UK) to net sales, usually expressed in percent. Net profit measures the profitability of ventures after accounting for all costs. Return on sales (ROS) is net profit as a percentage of sales revenue. ROS is an indicator of profitability and is often used to compare the profitability of companies and industries of differing sizes. Significantly, ROS does not account for the capital (investment) used to generate the profit. In a survey of nearly 200 senior marketing managers, 69 percent responded that they found the "return on sales" metric very useful. Unlike Earnings before interest, taxes, depreciation, and amortization (EBITDA) margin, operating margin takes into account depreciation and amortization expenses. {NNP = GNP- depreciation /GNP = GDP- depreciation Purpose These financial metrics measure levels and rates of profitability. Probably the most common way to determine the successfulness of a company is to look at the net profits of the business. Companies are collections of projects and markets, individual areas can be judged on how successful they are at adding to the corporate net profit. Not all projects are of equal size, however, and one way to adjust for size is to divide the profit by sales revenue. The resulting ratio is return on sales (ROS), the percentage of sales revenue that gets 'returned' to the company as net profits after all the related costs of the activity are deducted. Construction Net profit measures the fundamental profitability of the business. It is the revenues of the activity less the costs of the activity. The main complication is in more complex businesses when overhead needs to be allocated across divisions of the company. Almost by definition, overheads are costs that cannot be directly tied to any specific product or division. The classic example would be the cost of headquarters staff. Net profit: To calculate net profit for a unit (such as a company or division), subtract all costs, including a fair share of total corporate overheads, from the gross revenues.Return on sales (ROS): Net profit as a percentage of sales revenue. Earnings Before Interest, Taxes, Depreciation, and Amortization (EBITDA) is a very popular measure of financial performance. It is used to assess the 'operating' profit of the business. It is a rough way of calculating