Profit margin represents the percentage of revenue that a company keeps as profit after accounting for fixed and variable costs. It is calculated by dividing net income by revenue. The profit margin is mainly used for internal comparisons, because acceptable profit margins vary between industries. In general, narrow profit margins indicate increased volatile earnings. For companies with significant fixed costs, wide profit margins reduce the risk that a decline in sales will cause a net profit loss.
Displayed as a percentage, profit margin can be thought as the amount of profit that a company keeps per dollar of revenue. For example, if a company has a profit margin of 43%, the company keeps $.43 of each dollar of revenue.
Profit Margin = Net Income / Revenue