Inventory Turnover, Days and Carrying Cost Calculator
Reviewed by Finin2min Editorial Desk · Last reviewed 11 August 2026
Calculate average inventory, turnover, inventory days and annual carrying cost.
Inventory inputs
Inventory turnover
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Inventory days
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Average inventory
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Annual carrying cost
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Calculation guidance will appear here.
How This Is Calculated
Inventory turnover = Cost of Goods Sold ÷ average inventory — a higher turnover generally indicates efficient inventory management, while a low turnover can signal overstocking or slow-moving inventory. Days of inventory outstanding converts this ratio into an average number of days inventory sits before being sold.
Frequently Asked Questions
What is considered a "good" inventory turnover ratio?
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It varies significantly by industry — fast-moving consumer goods typically have much higher turnover than, say, heavy machinery or luxury goods. Compare your turnover against industry benchmarks and your own historical trend rather than a universal target.
Why does average inventory (not ending inventory) get used in the turnover formula?
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Because ending inventory alone can be misleading if it's unusually high or low at period-end due to timing — averaging opening and closing inventory smooths out that timing distortion, giving a more representative turnover figure for the period.
Inventory turnover should use cost of goods sold against average inventory for a comparable period. Days inventory is a derived operating metric; using revenue instead of COGS can distort comparisons in low/high-margin businesses.
Use beginning/end or more frequent average inventory where seasonality is material. A high turnover is not automatically good if it reflects stock-outs or weak service levels.
Input integrity
Use source documents rather than approximate memory.
Confirm period, units, tax regime/category and sign conventions.
Test zero, threshold and just-above-threshold cases where relevant.
Output interpretation
Separate arithmetic output from legal eligibility/classification.
Preserve assumptions and the official-source date.
Use the linked detailed guide for exceptions and evidence.
Scope: Computes inventory turnover ratio, days inventory outstanding, and estimated carrying cost, to assess how efficiently inventory is being managed.
Calculation logic
Inventory turnover ratio = Cost of goods sold (COGS) for the period ÷ Average inventory value for the period.
Days inventory outstanding = Number of days in the period ÷ Inventory turnover ratio.
Annual carrying cost = Average inventory value × Carrying cost percentage (covering storage, insurance, obsolescence and capital cost, as entered by the user).
Inputs and assumptions
Average inventory is computed as (Opening inventory + Closing inventory) ÷ 2, the standard convention, unless the user enters a different average directly.
Carrying cost percentage is a user-entered assumption reflecting the business's own storage, insurance and capital cost structure.
Exclusions and edge cases
Does not break down turnover by SKU or product category — this is an aggregate, business-level calculation.
Seasonal inventory build-up/drawdown patterns are not separately modelled; use a shorter period (e.g., quarterly) for more granular seasonal analysis.
Sources
No external regulatory source applies — this is a general financial formula, not a statutory computation.
Review status: reviewed and approved by CA Nikhil Gupta on 18 July 2026.
Guides on this topic
Background, worked examples and the rules behind these numbers.