Inventory turnover measures how efficiently a business sells and replaces its stock. High turnover means strong sales and lean operations. Low turnover signals overstocking, sluggish demand, or potential obsolescence. Whether you're a retailer, analyst, or business owner, understanding this metric drives smarter purchasing, better cash flow, and stronger margins.
What Is Inventory Turnover?
Inventory turnover is a ratio that shows how many times a company sells through its entire inventory during a given period — typically one year. A turnover ratio of 6 means the business cycled through its full stock six times, or roughly every two months.
The metric matters because inventory ties up cash. Stock sitting on shelves costs money in storage, insurance, and opportunity. Businesses that turn inventory quickly free up working capital, reduce carrying costs, and leave less room for products to become obsolete or damaged.
Days Sales of Inventory (DSI) is the companion metric. It converts turnover into days, answering: how long does the average item sit before it sells? A turnover of 6 equals a DSI of roughly 61 days (365 ÷ 6). Together, these two numbers give you the full picture.
Inventory turnover is also used as a percentage benchmark. Inventory as a percentage of sales — calculated as average inventory divided by net sales — helps buyers, analysts, and lenders gauge asset efficiency across companies of different sizes.
How to Calculate Inventory Turnover
The core inventory turnover formula is:
Inventory Turnover = Cost of Goods Sold (COGS) ÷ Average Inventory
Step 1 — Find COGS. Use the formula: Beginning Inventory + Purchases − Ending Inventory. If you started with $80,000, bought $500,000 more, and ended with $100,000, your COGS is $480,000.
Step 2 — Calculate average inventory. Add beginning and ending inventory, then divide by 2. A beginning balance of $90,000 and ending balance of $110,000 gives average inventory of $100,000.
Step 3 — Divide. $480,000 COGS ÷ $100,000 average inventory = 4.8 turns.
Step 4 — Convert to DSI (optional). 365 ÷ 4.8 = 76 days. The average item sits on the shelf for about 76 days before it sells.
For seasonal businesses, use monthly inventory snapshots and average all 12 figures for a more accurate denominator. A single year-end snapshot can distort the calculation if inventory peaks or troughs sharply at year-end.
How to Interpret Your Results
Context is everything. A "good" inventory turnover ratio depends entirely on your industry.
Grocery and food service turn inventory 15–30 times annually. Perishables demand it. A restaurant with $400,000 in annual food costs and $15,000 average inventory achieves ~27 turns — stock cycles every 13 days.
Fashion retail averages 4–6 turns (60–90 days). Fast-fashion brands push 8–10 turns through frequent new arrivals and aggressive markdowns.
Furniture and appliances typically achieve 3–5 turns. High unit costs and the need to display variety slow the cycle.
Auto dealerships run 6–8 turns. Specific customer preferences (color, trim, features) require maintaining wider selection.
Industrial suppliers and distributors vary from 4–12 turns depending on product type.
Use these benchmarks to calibrate your own number. A ratio of 4 is excellent for a furniture showroom but dangerously slow for a fresh produce distributor. Compare within your sector, not across all businesses.
One warning: very high turnover isn't automatically better. If turnover spikes because you slashed inventory, you may be creating stockouts — losing sales because popular items aren't available when customers want them.