Find your turnover ratio and days of inventory — how fast stock becomes cash.
Inventory is cash wearing a disguise — cash that cannot pay rent until it sells. Our free Inventory Turnover Calculator measures how fast your stock converts back into cash: the turnover ratio (how many times per year you sell through your inventory) and days of inventory outstanding (how long each dollar of stock sits before selling).
Inventory turnover = annual cost of goods sold (COGS) ÷ average inventory value. A ratio of 5 means you sell and replace your entire stock five times a year; equivalently, the average item sits 73 days (365 ÷ 5) before selling. High turnover means lean, cash-efficient operations; low turnover means capital trapped on shelves.
Enter your annual COGS and average inventory value (beginning + ending inventory ÷ 2) to get both numbers instantly, with a read on whether your turnover is fast, healthy, or sluggish. Retailers, wholesalers, Amazon sellers, and manufacturers live by this ratio — now you can check yours in one click.
The turnover ratio answers “how many times did my stock sell through this year?” Days of inventory outstanding (DIO) answers the same question in days: 365 ÷ turnover. Both come from one division; DIO is usually the more intuitive number — “73 days of stock” is easier to act on than “5.0 turns.”
Why it matters: inventory has a carrying cost — typically 20–30% of inventory value per year once you add warehousing, insurance, shrinkage, obsolescence, and the opportunity cost of the capital. $50,000 of average inventory at 25% carrying cost burns $12,500 a year just sitting there. Cut average inventory to $35,000 at the same COGS and turnover rises from 5.0 to 7.1, DIO falls from 73 to 51 days, and carrying cost drops $3,750 — pure profit, no extra sales needed.
Benchmarks vary wildly by industry, which is why the widget’s verdict is a starting point, not a grade. Grocery turns 10–15× (perishables force it); apparel turns 3–5×; auto dealers turn ~2×; luxury goods can turn below 1× deliberately. Compare yourself to your category and your own history — a falling ratio at your own store is the real warning, whatever the absolute number.
The ratio has a twin danger at each extreme. Too low means overstock: cash trapped, markdowns coming, obsolescence risk (fashion, tech, perishables). Too high means stockouts: lost sales, expedited reorders, and customers who learn you never have what they want. The optimum is the highest turnover you can sustain without stockouts — which is why turnover is always read alongside fill rate.
Key terms:
Use COGS, not revenue — inventory is valued at cost, so the numerator must be at cost too, or the ratio mixes price levels. Use the average inventory, not year-end, because seasonal businesses end the year at unrepresentative levels.
A home-goods store: annual COGS $250,000, beginning inventory $58,000, ending inventory $42,000.
Now suppose the owner trims slow SKUs and average inventory falls to $40,000 with COGS unchanged: turnover = 6.25×, DIO = 58.4 days, and carrying cost (at 25%) falls from $12,500 to $10,000 — $2,500 of annual profit from editing the catalog, not selling more.
A specialty grocer: COGS $1,200,000, average inventory $80,000.
For perishables, turnover is not just financial — it is physical. Every extra day of DIO is measurable waste. Grocery buyers manage to the ratio daily, not annually.
An Amazon seller holds $120,000 of inventory turning 4× (DIO 91 days). Amazon’s storage fees and long-term storage surcharges punish exactly this profile: after 365 days, per-cubic-foot monthly fees can exceed the item’s margin. Raising turnover to 6× by cutting the tail of slow ASINs drops average inventory to $80,000, frees $40,000 of cash, and dodges the aged-inventory fees — the ratio is the lever, the fees are the motive.
A boutique carries $60,000 of inventory at 2.2× (DIO 166 days) — nearly half a year of stock. Carrying cost at 25%: $15,000/year. The owner resists markdowns on “good product,” but the math is brutal: a 30% markdown that lifts turnover to 3.5× costs less than another year of carrying cost on dead stock. Slow turnover makes markdowns cheaper than patience — a sentence every overstocked retailer should frame. (Markdown math belongs with the discount calculator in related links.)
A distributor turns 8× but stockouts monthly. The ratio looks great; the fill rate does not. Analysis shows the average hides variance: fast movers stock out while slow movers gather dust. The fix is not a higher ratio — it is ABC analysis: A-items (top 20% of sales) get safety stock, C-items get cut. Turnover by category, not in aggregate, is the diagnostic that finds this.
A manufacturer’s raw-materials turnover is 3× while finished-goods turnover is 9× — cash is trapped upstream. Renegotiating supplier lead times from 60 to 30 days lets raw inventory halve, releasing working capital without touching production. Turnover computed per stage (raw, work-in-progress, finished) shows exactly where the cash is stuck; the aggregate ratio hides it.
Carrying cost, itemized: the 20–30% rule of thumb breaks into capital cost (8–12%: what the money could earn), storage (4–8%), risk — obsolescence, shrinkage, damage (5–10%) — and service costs like insurance and taxes (2–4%). Fashion and consumer electronics live at the high end (obsolescence); staples at the low end. Know your own number: multiply it by average inventory and the annual cost of your stock level stares back at you.
Worked scenario — the cash-conversion story: a wholesaler: DIO 73 days, receivables 45 days, payables 30 days → cash conversion cycle = 73 + 45 − 30 = 88 days. Every dollar of COGS is out of pocket for 88 days. Cutting DIO to 55 (turnover 6.6×) shortens the cycle to 70 days — on $1M COGS that frees roughly $49,000 of working capital (18 days ÷ 365 × $1M). Turnover is not an academic ratio; it is the biggest lever on how much cash a growing business must raise.
Edge cases and pro tips: seasonal businesses should compute turnover on trailing-twelve-month COGS with average inventory over the same period — a December year-end inventory after holiday sell-through understates the average and flatters the ratio. Service businesses with no inventory get a meaningless infinite ratio; track utilization instead. Consignment stock is not your inventory — exclude it. And never compare your ratio to another industry’s: a grocer’s 15× and a jeweler’s 1× can both be excellent.
When this calculator is the wrong tool: it gives the aggregate ratio. SKU-level decisions need ABC/XYZ analysis; reorder timing needs EOQ and safety-stock math; and profitability needs margin analysis (related links). Use this widget for the headline number and trend — then drill down where it points.
Inventory turnover = annual COGS ÷ average inventory; DIO = 365 ÷ turnover. Higher turnover frees working capital; carrying cost ~20–30%/year. Benchmarks are industry-specific. Source: Sigma Calculator, Inventory Turnover Calculator, https://sigmacalculator.net/e-commerce-calculators/inventory-turnover-calculator/
Cite this page as: Inventory Turnover Calculator, Sigma Calculator, https://sigmacalculator.net/e-commerce-calculators/inventory-turnover-calculator/
Last updated: October 12, 2026