How to use the Days Inventory Outstanding (DIO) Calculator
The Days Inventory Outstanding (DIO) Calculator works out your days inventory outstanding in an instant. Enter average inventory, cost of goods sold and days in period and the result updates as you type — it is free, needs no sign-up, and runs entirely in your browser so your figures stay private.
Enter the average inventory.
Enter the cost of goods sold.
Enter the days in period.
Read off your days inventory outstanding — the calculator updates automatically, with no button to press.
Formula
The Days Inventory Outstanding (DIO) Calculator uses the formula:
Days inventory outstanding = Average inventory ÷ Cost of goods sold × Days in period
Worked example
For example, with average inventory of 30,000, cost of goods sold of 219,000 and days in period of 365, the days inventory outstanding is 50.0.
Inputs used
Average inventory
30,000
Cost of goods sold
219,000
Days in period
365
Results
Days inventory outstanding
50.0
Results are estimates for educational use, not professional advice.
The average of a set of numbers — their sum divided by how many there are.
Frequently asked questions
DIO is the average number of days stock sits before being sold: average inventory ÷ cost of goods sold × days in period.
Lower DIO means inventory sells quickly, freeing cash and reducing storage and obsolescence risk.
Yes. A very low figure may mean too little stock, risking stockouts and lost sales.
It is one part of the cash conversion cycle, alongside days sales outstanding and days payable outstanding.
The Days Inventory Outstanding (DIO) Calculator uses the formula: Days inventory outstanding = Average inventory ÷ Cost of goods sold × Days in period. For example, with average inventory of 30,000, cost of goods sold of 219,000 and days in period of 365, the days inventory outstanding is 50.0.
Enter the average inventory. Enter the cost of goods sold. Enter the days in period. Read off your days inventory outstanding — the calculator updates automatically, with no button to press.
Reference table of days inventory outstanding for Days Inventory Outstanding (DIO) across a range of average inventory values — exact, engine-computed figures you can read off at a glance.
Learn how to calculate Days Inventory Outstanding (DIO) — the formula explained step by step, with worked examples and a free calculator to check your answer.