Efficiency Ratios
Inventory Days
Inventory Days, or Days Inventory Outstanding, translates inventory turnover into the average number of days inventory is held.
Concept First
Learn It Step By Step
Start with the business meaning, then move into the formula.
What is Average Inventory?
Inventory is stock held for sale or production, such as raw material, work-in-progress, finished goods, or traded goods. It is a current asset because it should normally move into sales, but it is not the same as cash; it must first be sold and then collected. For example, a manufacturer may hold steel as raw material, partly finished components as work-in-progress, and packed goods ready for dispatch as finished goods.
What is COGS?
Cost of goods sold: the cost of material or goods consumed to generate the sales of the period, not merely purchases made. Example: raw material and goods consumed to make the products sold during the period.
How should I read the answer?
Lower inventory days means faster cash conversion. The source notes FMCG may be 15 to 30 days, while manufacturing often runs 45 to 90 days.
Formula Lab
Understand the Formula
Read the formula like a business sentence before calculating it.
Formula
365 / Inventory Turnover, or Average Inventory / COGS x 365
Interpretation
What This Means In Practice
Read the result as a business signal, not as a standalone number.
Efficiency must still protect operations
Lower inventory days means faster cash conversion. The source notes FMCG may be 15 to 30 days, while manufacturing often runs 45 to 90 days. Faster turnover or fewer days is useful only when it does not damage customer service, supplier relationships, production continuity, or sales growth.
What the number is really asking
Inventory Days is more intuitive than turnover because it expresses stock holding in time. The business question is how much revenue or cash is produced for every rupee tied up in inventory, receivables, payables, working capital, or assets.
Key Takeaway
Inventory Days is more intuitive than turnover because it expresses stock holding in time.
Practice Checkpoint
Check Your Understanding
Work through the quiz in smaller sets. Your answers stay visible while this page is open, so you can review before moving on.
Question 1 of 20
Level 1What does lower the result usually indicate?
Question 2 of 20
Level 1Why is the result easier for managers than turnover?
Question 3 of 20
Level 1The result rising sharply while sales are flat suggests:
Question 4 of 20
Level 1Which underlying item must you understand before calculating or interpreting the result?
Question 5 of 20
Level 1Which statement is the best conceptual reading of this measure?
15 questions remaining in this lesson.
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