Inventory Turnover Calculator
Calculate how many times your inventory sells and is replaced during a period, and how many days inventory sits on the shelf before sale. Faster turnover means less cash tied up in stock — a key working capital metric.
What Is Inventory Turnover?
Inventory turnover measures how many times a business sells and replaces its entire inventory during a period, usually a year. A turnover of 4.5 means the business clears its average inventory 4.5 times per year — roughly every 80 days.
Higher turnover is generally better — it means inventory moves quickly and cash is not tied up in unsold stock. But turnover that is too high can indicate understocking, which leads to stockouts and lost sales. The right number depends on the product and industry.
Inventory Turnover Formula
Average Inventory = (Beginning Inventory + Ending Inventory) ÷ 2
Inventory Turnover = COGS ÷ Average Inventory
Days Inventory Outstanding = 365 ÷ Inventory Turnover
Days Inventory Outstanding (DIO) — also called days sales of inventory — is the inverse of turnover. It tells you the average number of days a unit of inventory sits before being sold.
Worked Example
A business has $500,000 in COGS, $100,000 beginning inventory, and $120,000 ending inventory:
Average inventory = ($100,000 + $120,000) ÷ 2 = $110,000
Inventory turnover = $500,000 ÷ $110,000 = 4.55× per year
DIO = 365 ÷ 4.55 = 80.22 days
Interpretation: the business clears its average inventory about 4.5 times a year, roughly every 80 days. If the industry average is 6×, this business has excess stock and should look at slow-moving SKUs.
How to Interpret Inventory Turnover
- 8+ (Excellent) — very fast turnover. Common in grocery, FMCG, and fast fashion.
- 5–8 (Good) — healthy turnover for most retail and distribution.
- 3–5 (Average) — acceptable but may indicate excess stock or slow-moving SKUs.
- Below 3 (Poor) — inventory is sitting too long. Cash is tied up, and obsolescence risk is high.
- Very high turnover — could mean understocking and stockouts. Check if you are losing sales to out-of-stocks.
Frequently Asked Questions
What is a good inventory turnover?
It varies widely by industry. Grocery and FMCG: 10–15×. Apparel and retail: 4–8×. Electronics: 5–10×. Auto parts: 3–5×. Furniture: 2–4×. Compare against the industry benchmark, not against an arbitrary number. A turnover of 5× is good for furniture but poor for groceries.
Why is inventory turnover important?
Inventory is one of the largest cash sinks in most product businesses. Slow turnover means cash is tied up in stock that is not selling. Faster turnover frees that cash for operations, debt repayment, or growth. It also reduces storage costs, obsolescence risk, and markdown losses.
What is the difference between inventory turnover and DIO?
They are inverses of each other. Inventory turnover tells you how many times inventory is replaced per year; DIO tells you how many days it takes to sell. A turnover of 6× per year equals a DIO of 61 days. Both describe the same underlying reality — the choice depends on whether days or multiples are more useful in your context.
Can inventory turnover be too high?
Yes. Very high turnover often means understocking — the business has so little inventory on hand that it cannot fill customer orders quickly. That leads to stockouts, lost sales, and damaged customer relationships. The optimal turnover balances cash efficiency with service levels.
Should I use average inventory or ending inventory?
Average inventory is more accurate because it smooths seasonal swings. Ending inventory is a single snapshot — if you end the year at a seasonal low, ending inventory will understate true inventory and overstate turnover. Use average when both beginning and ending figures are available.
How do I improve inventory turnover?
Several levers: stop stocking slow-moving SKUs, negotiate smaller and more frequent purchase orders with suppliers, use demand forecasting to align stock with sales, discount or liquidate excess stock, and tighten the product catalog. Fast turnover often comes from cutting the long tail of products, not from selling more of the top sellers.