Delia Mancuso walked a lender through Sixth Street Strings, her vintage guitar shop in Reno, and pointed at $312,000 of inventory on the balance sheet as evidence the business was solid. The loan officer asked one question that ended the conversation.
How much of it sold last year?
She went home and pulled the numbers. Of the 340 instruments on her floor, 118 had been hanging on the wall for more than 24 months. Those 118 represented $147,000 in capital, sitting under fluorescent lights, doing nothing except appearing valuable on a financial statement.
Inventory is the one current asset that lies to you. Cash is cash. Receivables usually get collected. Inventory is worth whatever someone eventually pays for it, and the balance sheet quietly assumes that day is coming.
The ratio that tells the truth
Inventory Turnover = COGS / Average Inventory Value
Average Inventory = (Beginning Inventory + Ending Inventory) / 2
Cost of goods sold goes in the numerator, not revenue. Inventory is carried at cost, so using sales figures mixes cost with markup and inflates the ratio. A shop using revenue can show a turnover of 6 when the real number is 4.
A turnover of 6 means the business sold and replaced its entire stock six times in the period. The companion figure converts that into something more intuitive.
Days Inventory Outstanding = 365 / Inventory Turnover
Delia's numbers for the year: COGS of $694,000, beginning inventory of $296,000, ending inventory of $328,000.
Average Inventory = ($296,000 + $328,000) / 2 = $312,000
Inventory Turnover = $694,000 / $312,000 = 2.2 turns
DIO = 365 / 2.2 = 166 days
An average instrument sat on her wall for five and a half months. Her dead stock skewed that badly, which is precisely what an average is supposed to reveal.
There is no universal good number
| Business type |
Typical annual turns |
| Grocery and perishables |
12 to 26 |
| Fashion and apparel retail |
8 to 10 |
| General merchandise and manufacturing |
4 to 6 |
| Specialty and big-ticket items |
1 to 3 |
Perishable goods force high turnover because the alternative is spoilage. A dealer in vintage instruments or classic car parts operates at 1 or 2 turns and does so profitably because the margin per unit is high enough to justify holding time.
Comparing your ratio to a different industry produces nonsense. Comparing it to your number from last quarter produces information.
When high turnover is also a problem
High turns usually signal strong sales and lean purchasing. They can also signal that you are chronically understocked.
A business turning inventory 14 times when its category norm is 8 may be losing sales it never records. Stockouts do not appear anywhere in the accounts. There is no line item for the customer who wanted a preamp on Saturday, found an empty peg, and bought it online instead. Rush reorders, expedited freight, and higher per-unit costs from smaller purchase quantities all show up as margin compression rather than as an inventory problem.
The balance point sits between two costs that move in opposite directions: carrying cost when you hold too much and stockout cost when you hold too little.
Lead time decides where that point sits. A supplier who ships in four days lets you run lean safely. A supplier with a six-week lead time and unreliable fill rates forces safety stock onto your shelves, which drags turnover down for reasons that have nothing to do with how well you sell. The ratio measures the outcome and says nothing about the cause, so a declining number is the start of an investigation rather than a verdict.
Timing distorts it too. A retailer who builds stock in October for December shows terrible turnover on an October 31 balance sheet and excellent turnover on January 31. Averaging inventory over the period smooths this distortion, and comparing the same quarter year over year is more meaningful than comparing month to month.
What the shelves actually cost
Carrying Cost Ratio = Total Carrying Costs / Average Inventory Value × 100
Carrying costs include warehouse or floor space, insurance, financing on the capital tied up, handling labor, shrinkage, and obsolescence. For most businesses, it runs 20% to 30% of inventory value annually.
Applied to Delia's $147,000 of dead stock at a 22% carrying rate, this means roughly $32,000 a year to store instruments that are not selling. Her net income last year was $61,000.
A second ratio isolates the problem directly.
Obsolete Inventory Ratio = Value of Items With No Recent Usage / Total Inventory Book Value
Her figure: $147,000 / $312,000 = 47%. Nearly half her inventory had no sales activity in 24 months.
The margin question that changes decisions
Turnover alone ignores profitability. A product turning 10 times at 8% margin and one turning 3 times at 30% margin deserve different treatment, and gross margin return on investment sorts them out.
GMROI = Gross Profit / Average Inventory Cost
A GMROI above 1.0 means each dollar in inventory generates more than a dollar in gross profit. Below 1.0 means the product line consumes more capital than it returns, regardless of how respectable the turnover looks.
This is why cutting slow stock across the board is a mistake. Some slow items carry the margin that funds everything else.
What Delia had to do
She ran a 90-day clearance on 74 instruments at an average 31% discount, recovered $71,000 in cash, and took a real loss against book value on most of them. Painful and correct. The capital had already been losing 22% a year to carrying costs while pretending to be an asset.
She reinvested in the categories her sales data actually supported, cut her buying on consignment terms where possible, and finished the following year at 3.8 turns with a DIO of 96 days.
The number to pull this month
Run turnover by category, not just for the whole business. A single blended ratio hides the difference between the shelf that funds your payroll and the shelf that quietly bills you every month.
Then ask the question the loan officer asked. Not what the inventory is worth on paper, but how much of it moved. Full shelves are inventory. Empty shelves that keep refilling are the goal of your business.
