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Days Sales in Inventory (DSI)

Calculate Days Sales in Inventory

What is Days Sales in Inventory (DSI)?

Days Sales in Inventory (DSI), sometimes known as inventory days or days in inventory, is a measurement of the average number of days or time required for a business to convert its inventory into sales. The days sales in inventory value is calculated by dividing the inventory balance (including work-in-progress) by the amount of cost of goods sold. This number is then multiplied by the number of days in a year, quarter, or month.

Below is an example of annual data:

Days Sales in Inventory (DSI) formula


The DSI figure represents the average number of days that a company’s inventory assets are realized into sales within the year. Days sales in inventory is also one of the measures used to determine the cash conversion cycle, which is the company’s average days to convert resources into cash flows.


What is the Formula for Days Sales Inventory (DSI)?

To determine how many days it would take to turn a company’s inventory into sales, the following formula is used:


DSI =  (Inventory / Cost of Sales) x (# of Days in the Period)



For the year-end 2015 financial statements, Target Corp. reported an ending inventory of $1M and a cost of sales of $100M. Given the figures, the days sales inventory for the year is 3.65 days, meaning it takes approximately 4 days for the company to sell its stock of inventory.


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What are the Indications of Low and High DSI?

Generally, a small average of days sales, or low days sales in inventory, indicates that a business is efficient, both in terms of sales performance and inventory management. Hence, it is more favorable than having a high days sales in inventory. A low days sales in inventory reflects fast sales of inventory stocks and thus would minimize handling costs, as well as increase cash flow.

On the other hand, a high days sales in inventory value generally indicates either a slow sales performance or an excess of purchased inventory (the company is buying too much inventory), which may eventually become obsolete. However, it may also mean that a company with a high days sales in inventory has been maintaining high inventory levels to meet high customer demand.

It is also important to note that the average days sales in inventory differs from one industry to another. To obtain an accurate days sales in inventory value comparison between companies, it must be done between two companies within the same industry or that conduct the same type of business. For instance, a retail store like Wal-mart can be compared to Costco in terms of inventory and sales performance.


How Important is Days Sales Inventory to Businesses and Investors?

For a company that sells more goods than services, days sales in inventory is an important indicator for creditors and investors, because it shows the liquidity of a business. These interested parties would want to know if a business’s sales performance is outstanding; therefore, through this measurement, they can easily identify such.

The more liquid the business is, the higher the cash flows and returns will be. Management is also interested in the company’s days sales in inventory to determine how fast inventory moves, which is important when taking storage and maintenance expenses of holding inventory into account.

The carrying cost of inventory, which includes, rent, insurance, storage costs, and other expenses related to holding inventory, may directly impact profit margin if not managed properly.  In addition, the longer the inventory is kept, the longer its cash equivalent isn’t able to be used for other operations and, thus, opportunity cost is lost.



Additional resources

Thank you for reading CFI’s guide to calculating Days Sales in Inventory (DSI). CFI is the official provider of the Financial Modeling & Valuation Analyst designation and on a mission to help you advance your career. These additional CFI resources will help you continue to advance your career:

  • Inventory turnover
  • Asset turnover
  • Accounts receivables
  • Normalizing financial statements

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