Days Inventory Outstanding Calculator

Calculate Days Inventory Outstanding (DIO)

Days Inventory Outstanding (DIO), also known as Days Sales of Inventory (DSI), measures the average number of days a business holds inventory before converting it into sales. DIO is a key component of the cash conversion cycle and evaluates working capital management efficiency.

Days Inventory Outstanding Formula

DIO is calculated using the following mathematical formula:

$$\text{DIO} = \left(\frac{\text{Average Inventory}}{\text{Cost of Goods Sold (COGS)}}\right) \times \text{Days in Period}$$

Where Average Inventory is the arithmetic mean of beginning and ending inventory values:

$$\text{Average Inventory} = \frac{\text{Beginning Inventory} + \text{Ending Inventory}}{2}$$

Interpreting Your DIO Result

The optimal DIO depends heavily on your industry:

• Lower DIO: Indicates rapid inventory turnover, reduced holding costs, and efficient supply chain management.
• Higher DIO: May suggest overstocking, low sales demand, obsolete inventory, or inefficient capital allocation.

Related Financial Metrics

Analyze inventory performance further with our Cost of Goods Sold Calculator, or examine working capital cycle metrics with our AR Days Calculator.