Nearly one in five wholesalers doesn't even know how many days of coverage their stock represents. And among those who do, most carry far more inventory than they likely need — not as a strategy, but out of habit. Here we quantify it with sector data and walk through the math to calculate your own number.
Days Inventory Outstanding (DIO) measures how long your stock sits in the warehouse before it sells. It's one of the most direct signals of how much working capital you have tied up without needing to be.
Where wholesalers actually stand
Per the 2026 Phocas Wholesale Distribution Inventory Trends report, the most common range among wholesale distributors is 61 to 90 days of supply, with 32% of respondents in that bracket. Combining the 31–60 and 61–90 day ranges, 47% of wholesalers carry between one and three months of stock — which the report itself describes as a "buffer" approach rather than a deliberate lean-inventory strategy. And a striking data point: 19% of respondents admitted they don't know which range their own company falls into.
Not knowing your DIO isn't a minor gap — it means not knowing how much of your working capital is sitting on a shelf instead of working for the business.
The "normal" number depends heavily on your sector
There's no universal "good" DIO. The most commonly cited sector references put retail at 30–60 days, manufacturing at 60–120 days, technology companies at 20–40 days (due to obsolescence risk), and pharmaceuticals at 120–180 days (due to regulatory and availability requirements). A wholesaler of fast-turning goods sitting at 90 days of coverage is out of range; a distributor of industrial parts with the same number may be perfectly normal.
The math: your real DIO
DIO = (average inventory ÷ annual cost of goods sold) × 365
Illustrative example (sample figures — swap in your own in the calculator below): a wholesaler with €150,000 in average inventory and €900,000 in annual cost of goods sold has a DIO of (150,000 ÷ 900,000) × 365 = ≈ 61 days. Right in the sector's most common range per the report above — though that doesn't automatically mean it's the right number for this particular business, only that it isn't alone in that bracket.
Calculated SKU by SKU instead of at the business level, this same math reveals which specific products are inflating your average DIO — usually a handful of slow-moving items, not the whole catalog equally.
Calculate your days of inventory by SKU
Upload your catalog as a CSV and calculate how many days of coverage each SKU's current stock provides — with a free account you'll see which SKUs need attention first and the trend versus your last upload.
Go to the days of inventory calculator →What to do with this
- If you don't know your current DIO, that's step one — you can't decide whether your stock is too high or too low without a starting number.
- Calculate DIO per SKU, not just at the aggregate level — a "normal" average can hide items sitting at 200+ days of coverage, offset by others that turn over weekly.
- Benchmark your number against your specific subsector, not a generic figure — 90 days can be a warning sign or completely reasonable depending on what you sell.
Sources
- Distribution of days-of-supply among wholesalers and the share unaware of their own DIO (2026 Wholesale Distribution Inventory Trends): Phocas Software, "Days in inventory (DIO) formula and why it's useful" .
- DIO reference ranges by sector (retail, manufacturing, technology, pharmaceutical): Xepelin, "DIO o Días promedio de inventario: qué son y cómo mejorarlos".
The average inventory and cost of goods sold in the worked example are illustrative — built from sample numbers to explain the calculation, not a statistic about any industry. Swap in your own business's real numbers using the calculator.