Inventory turnover is the number of times a business sold and replaced its inventory across a period, calculated as the cost of goods sold for that period divided by the average inventory balance held across it. The answer is a count of times rather than a percentage or a dollar amount. Inventory turnover ratio, inventory turns and stock turn all name the same measure.
No accounting standard supplies the formula. Inventory turnover is one of the ratios computed from statement information rather than reported on the statements, and the SEC’s guide reads a ratio of 2 to 1 as inventory that turned over twice in the reporting period (SEC, Beginners’ Guide to Financial Statements). Because nothing fixes the wording, the version used has to travel with the number.
The Inventory Turnover Formula
inventory turnover = cost of goods sold / average inventory
average inventory = (opening inventory + closing inventory) / 2Cost of goods sold is what the units sold in the period cost to buy or make, which is not what was bought during the period. Goods bought and still standing at the close never reach it. Average inventory is what the business held, measured across the period rather than read at a single date, because the numerator covers a stretch of time and a balance sheet reports one day.
The SEC’s guide states it as cost of sales divided by average inventory for the period, and locates cost of sales just below net revenues on the income statement (SEC, Beginners’ Guide to Financial Statements). Whether the figure underneath is a two-point average or the closing balance alone is a stated choice rather than a rule, and the walkthrough of that average is set out in cash conversion cycle.
Both inputs are fixed by the close. The denominator comes off the inventory caption on the balance sheet, the numerator off the income statement caption for the period just closed, and a firm computing the count for a client is reading figures the close already produced rather than building anything new.
Why Inventory Turnover Uses Cost and Not Sales
Sales and the cost of goods sold are not interchangeable on top of this ratio, and swapping one for the other does not produce a stricter reading. It produces a different number.
Inventory is carried at cost. The primary basis of accounting for inventories is cost, which has been defined generally as the price paid or consideration given to acquire an asset, and inventories are presumed to be stated at cost (Accounting Research Bulletin No. 43, Chapter 4, Statement 3 and paragraph 5). Sales carry the markup added on the way out. Dividing a retail-priced numerator by a cost-based denominator counts that markup as though it were stock movement, so the answer comes out high in the same proportion sales stand above cost.
Nothing forces the substitution, because the two figures are separate captions on the same statement. Regulation S-X, the rule governing statements filed with the Commission, states net sales of tangible products at caption 1 and requires the cost of tangible goods sold to be stated separately at caption 2 (17 CFR 210.5-03). The payables side is the opposite case, where no purchases line appears among those captions at all, which is why AP turnover has to be built on a substitute.
One thing does travel with the caption. Merchandising organizations, both wholesale and retail, may include occupancy and buying costs under caption 2(a) (17 CFR 210.5-03), so a numerator lifted straight off a retailer’s statement can carry costs that never attached to a unit, and the room that leaves is worked through in overhead.
Which Inventory Sits Underneath
The reported caption is the whole pipeline, not the finished stock. Regulation S-X asks for the major classes of inventory to be stated separately where practicable, naming finished goods, inventoried costs relating to long-term contracts or programs, work in process, raw materials and supplies (17 CFR 210.5-02). A manufacturer’s count built on that total measures how fast the whole pipeline clears, and one built on finished goods alone measures something narrower. Neither is wrong, and the two cannot be set beside each other.
The cost flow assumption, the rule deciding which recorded costs move to expense when goods are sold, moves both figures at once. Cost for inventory purposes may be determined under any one of several assumptions as to the flow of cost factors, such as first-in first-out, average, and last-in first-out, and the major objective in selecting a method should be to choose the one which, under the circumstances, most clearly reflects periodic income (Accounting Research Bulletin No. 43, Chapter 4, Statement 4). The method sets the cost charged on top and the carrying amount left underneath together, so two businesses on different methods produce counts that are not comparable, a point the bulletin makes itself when it notes that financial statements will be more useful if uniform methods of inventory pricing are adopted by all companies within a given industry (Accounting Research Bulletin No. 43, Chapter 4, paragraph 7). What each assumption does to the two figures is set out in FIFO and LIFO.
A Worked Example
Say a distributor’s statements for the year carry the figures below.
Net sales 3,600,000
Cost of goods sold 2,160,000
Inventory, opening 330,000
Inventory, closing 390,000
average inventory (330,000 + 390,000) / 2 = 360,000
inventory turnover 2,160,000 / 360,000 = 6.0 times
the same year on sales 3,600,000 / 360,000 = 10.0 timesSame stock and the same year, and the second count is higher by exactly the markup the goods carried on the way out. It reports a business clearing its shelves ten times when what actually left them cost six times what was standing there on an average day.
Dividing the days in the year by the count converts it into the days form, and the day-count and averaging conventions that move that answer are set out in days inventory outstanding.
What Inventory Turnover Is Commonly Confused With
Days inventory outstanding, days inventory on hand and days sales of inventory are the same relationship expressed as a duration rather than a count, so a figure quoted in days is not a turnover and the two do not read on the same scale.
A count built on sales is not this ratio computed a different way, and it reports more turns than the goods actually made.
Common Questions
It is a count of how many times a business sold and replaced its inventory across a stated period. The period belongs with the number, because a count taken over a year and a count taken over a quarter are not the same measure.
Take the cost of goods sold for the period, divide by the average inventory balance for that same period, and state which inventory figure went underneath alongside the answer.
There is no authoritative figure. Desirable ratios vary by industry as a general rule (SEC, Beginners’ Guide to Financial Statements), and a level quoted as an industry norm is a house benchmark rather than a standard. What the count can honestly be measured against is the same business in earlier periods, the goods it actually sells, and another business whose figure was built on the same numerator, the same inventory classes and the same averaging convention.
Neither direction is a verdict on its own. A higher count means the same volume of sales was supported by less stock standing idle, and it also means less buffer against a supplier who runs late, so the same rise comes from tighter buying and from stock running short. A lower count means cash is sitting on the shelf, and it can equally be a deliberate cushion in front of a long lead time. What separates those readings is the reason the inventory balance moved, which the ratio never carries.
Accountably places trained offshore accountants and tax preparers inside US CPA and EA firms, and a firm can put a block of its own inventory costing and client statement work through a trial task before anything client facing depends on it.
