Here, you will discover how to calculate four key trading ratios — P/E, Price/book, ROE, and ROA — but luckily you can find all these where fundamental statistics are reported. Each of these ratios gives you just one more piece in the puzzle of determining how much you want to pay for a stock. By […] The following formulae are used to calculate the Stock Turnover Ratio. Inventory / Stock Turnover Ratio (Or) Stock Velocity = Cost of Goods Sold / Average Inventory at Cost. or. Inventory / Stock Turnover Ratio (Or) Stock Velocity = Net Sales / Average Inventory at Cost. or. Inventory / Stock Turnover Ratio (Or) Stock Velocity = Cost of Sales Source: d18rn0p25nwr6d.cloudfront.net Example – #3. Let us take the example of Walmart Inc. for the calculation of the stock turnover ratio. As per the company’s annual report for the year ending on January 31, 2018, the cost of sales for the year was $373,396 million and the inventory at the beginning of the year and at the end of the year was $43,046 million and $43,783 million respectively.