-The profit margin on this product during this time period. The margin is calculated as ([net sales - cost] / net sales) 100. For example, if your net sales are $50 and your cost is $30, then the gross margin (calculated as ([50 - 30] / 50) 100) is 40%. https://help.shopify.com/en/manual/reports-and-analytics/shopify-reports/report-types/profit-reports