Profit margin is a profitability ratio that measures, as a percentage, how much a company keeps per sale. Profit margin can be calculated by dividing net income by sales.
A higher profit margin means a company keeps high percentage of each dollar sold as profit. For example, a 50% profit margin means that for every dollar earned, a company retains $0.50.
It is often helpful for an analyst to look at how a company’s profit margins have changed over time, to measure whether it is becoming more efficient in the sales of goods.