Days Inventory Outstanding measures the average number of days a company holds inventory before selling it. A lower DIO indicates faster inventory turnover and more efficient operations. Together with DSO and DPO, DIO forms one of the three pillars of the Cash Conversion Cycle.
What It Is #
DIO tracks how long goods sit in storage, in production, or in transit before being converted into a sale. For manufacturing and retail businesses, inventory represents a significant capital investment — and every day that inventory sits unsold is a day that cash is tied up and unavailable for other uses.
Unlike DSO and DPO, which are primarily managed through financing and payment terms, DIO is more directly influenced by supply chain efficiency, demand forecasting, and inventory management practices.
The Formula #
DIO = (Average Inventory / Cost of Goods Sold) × Number of Days
DIO Across Industries #
| Industry | Typical DIO |
|---|---|
| Grocery retail | 15–25 days |
| E-commerce | 25–45 days |
| Consumer electronics | 30–50 days |
| Automotive manufacturing | 40–70 days |
| Pharmaceuticals | 60–100 days |
Reducing DIO with Financing #
While DIO is primarily an operational metric, inventory financing helps businesses manage it. Companies can hold optimal stock levels — including safety stock — without tying up excessive working capital, because financing covers the cost of inventory until it is sold.
This is particularly valuable for businesses with seasonal demand spikes, where building inventory ahead of peak periods would otherwise drain cash reserves.