Cost of goods sold (COGS)
COGS is the direct cost of the products you sold — what they cost you to buy or make.
Cost of goods sold (COGS) is the direct cost attributable to the products sold in a period: purchase or manufacturing cost, not overheads like marketing or rent. COGS is the missing half of profit — revenue alone doesn't tell you whether a product makes money. Subtract COGS from revenue and you get gross profit; the ratio is gross margin.
How it's measured
COGS = units sold × unit cost, summed across products. Store your landed unit cost per product to compute real profit.