how do i calculate ending inventory Calculating ending inventory is an essential task for businesses to determine the value of their remaining stock at the end of an accounting period. To calculate ending inventory, subtract the cost of goods sold (COGS) from the sum of beginning inventory and purchases made during the period. This figure helps businesses assess their stock levels, plan for reordering, and prepare for financial reporting. Accurate ending inventory calculations are vital for maintaining financial health and understanding product turnover.