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Quality & efficiency

Days Inventory Outstanding DIO

The average number of days a company holds inventory before it is sold.

Part of the Reading Financial Statements course · Lesson 38 of 39
Formula
DIO = (Average inventory / COGS) x 365
Average inventorystock on hand÷COGScost of sales=DIOdays to sell (×365)
DIO is the average number of days inventory is held before it is sold.

What it is

Days inventory outstanding (DIO) measures how long, on average, a company's inventory sits on the shelf before it is sold. It is average inventory divided by cost of goods sold (COGS, the direct cost of the items sold), times the number of days in the period. DIO is the inventory-holding leg of the cash conversion cycle.

Why it matters

A lower DIO means leaner, faster-moving inventory and less cash tied up in unsold goods, which supports liquidity and reduces obsolescence risk. The pitfall: chasing the lowest possible DIO can backfire, since inventory cut too thin risks stockouts and lost sales, and the "right" level is highly industry-specific. A jeweller or aircraft maker will run far higher DIO than a grocer, so judge DIO against the company's own trend and direct peers, not an absolute target.

How it's calculated

Divide average inventory (beginning plus ending inventory, divided by two) by cost of goods sold, then multiply by the number of days in the period, commonly 365 for a full year. The result is expressed in days.

How Quintarthai uses it

Inventory and cost of goods sold needed to compute DIO are on the Financials tab of a company deep-analysis page, and the related cash-conversion-cycle entry sits in the Knowledge Base.

Cross-border note. DIO is measured in days, so it compares cleanly across US and Canadian companies without currency conversion; just keep comparisons within the same industry, since inventory norms differ sharply by sector.

FAQ

Is a lower DIO always better?
Not always. Lower DIO frees up cash and cuts obsolescence risk, but if it falls too far the company may run out of stock and miss sales. The right level depends on the industry and the company's supply chain.
How does DIO relate to inventory turnover?
They are two views of the same thing. Inventory turnover is COGS divided by average inventory, and DIO is roughly 365 divided by that turnover, so a higher turnover means a lower DIO.
Check your understanding
A retailer reports average inventory of $50 million and annual cost of goods sold of $365 million. Using a 365-day year, what is its days inventory outstanding?
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