To calculate the gross profit margin, you need to find the difference between the net sales revenue and the cost of goods sold. The formula for calculating the gross profit margin is as follows:

Gross Profit Margin = (Net Sales Revenue - Cost of Goods Sold) / Net Sales Revenue

This ratio is then multiplied by 100 to express it as a percentage. The net sales revenue is typically found on the income statement, and the cost of goods sold includes the cost of materials and direct labor and overhead costs directly related to the production or acquisition of the goods. Keep in mind that the gross profit margin shows how much of each sales dollar is left over after covering direct costs associated with producing or acquiring the products.