Inventory Turnover Calculator
Measure how efficiently your business sells and replenishes inventory over a period. Use it to spot slow-moving stock, optimize ordering cycles, and benchmark against industry standards.
About this calculator
Inventory turnover measures how many times a business sells and replaces its entire stock within a given period. The formula is: Inventory Turnover = Cost of Goods Sold / Average Inventory, where Average Inventory = (Beginning Inventory + Ending Inventory) / 2. Using COGS rather than revenue removes the distortion of markup, giving a true picture of stock movement. A complementary metric is Days Sales of Inventory (DSI): DSI = Period Days / Inventory Turnover — this tells you how many days it takes, on average, to sell through your stock. A high turnover ratio signals strong sales or lean inventory management; a very high ratio may indicate stockouts. A low ratio suggests overstocking, obsolescence risk, or weak demand. Industry benchmarks vary widely: grocery stores may turn over 20–30× per year while furniture retailers may turn only 4–6×.
How to use
Assume your annual COGS is $480,000, beginning inventory is $60,000, and ending inventory is $100,000. Average Inventory = ($60,000 + $100,000) / 2 = $80,000. Inventory Turnover = $480,000 / $80,000 = 6.0. This means you sold through your entire stock 6 times during the year. To find DSI: 365 / 6.0 ≈ 61 days — on average, it takes about 61 days to sell your inventory. If competitors average 8×, you may be overstocking and tying up excess capital.
Frequently asked questions
What is a good inventory turnover ratio for retail businesses?
A 'good' ratio depends heavily on your industry. Grocery and fast-moving consumer goods retailers typically achieve 15–30 turns per year due to perishable, high-demand products. Apparel retailers often see 4–6 turns, while furniture or luxury goods may turn only 2–4 times annually. Comparing your ratio to industry averages is more meaningful than chasing an arbitrary number. Consistently improving your own ratio year over year while maintaining healthy stock levels is a reliable sign of operational efficiency.
Why is average inventory used instead of ending inventory in the turnover formula?
Using only ending inventory can distort the ratio if stock levels fluctuate significantly throughout the period — for example, if you run a seasonal business with high stock at year-start and low stock at year-end. Averaging beginning and ending inventory smooths out those fluctuations and provides a more representative snapshot of the inventory held during the period. For even greater accuracy, some analysts average monthly inventory balances across all 12 months, particularly in businesses with strong seasonal demand swings.
How can a low inventory turnover ratio hurt my business financially?
Low turnover means capital is sitting idle in unsold stock rather than being reinvested in growth, marketing, or better-performing products. Holding excess inventory increases storage costs, insurance, and the risk of spoilage or obsolescence — especially in fashion, technology, or perishable goods. It can also signal that your pricing is too high or that demand forecasting is misaligned with actual customer needs. Improving turnover through promotions, better demand forecasting, or supplier negotiations directly frees up working capital and improves cash flow.