Inventory Turnover Calculator: Ratio and Inventory Days (DIO)
Calculate inventory turnover, average inventory, and days inventory outstanding (DIO) for an annual, quarterly, or custom period.
Period
Result summary
Enter valuesAverage inventory
N/A
Inventory turnover
N/A
Times stock turned over in the period
Inventory days (DIO)
N/A
Use the same period for COGS (or net sales) and inventory figures. Currency is display-only and does not convert rates.
What is Inventory Turnover?
Inventory turnover compares cost of goods sold with average inventory over a selected period. It can help describe how inventory moves, but it is not a stand-alone measure of business efficiency: product mix, seasonality, stockouts, supplier lead times, and valuation methods affect interpretation. Pair it with inventory days (DIO) and item-level context.
Inventory Turnover Formula
Transparent math for turnover, average inventory, and days inventory outstanding.
Inventory Turnover
- Inventory Turnover = COGS ÷ Average Inventory
- Or (approximation): Net Sales ÷ Average Inventory
How to Calculate Inventory Turnover Using This Free Calculator
Enter COGS or Net Sales
Add Cost of Goods Sold for the period — or toggle Net Sales if COGS is not available.
Enter beginning and ending stock
The calculator finds average inventory automatically from the two values.
Choose your period
Use 365 days (annual), 90 days (quarterly), or a custom number of days.
Review ratio and DIO
See turnover, average inventory, and inventory days for the selected period.
Is Your Inventory Turnover Good or Bad?
A higher turnover ratio can mean inventory is moving quickly; a lower ratio can mean stock is moving more slowly. Either result needs context: product mix, seasonality, stock availability, supplier lead times, and sales plans all affect what is appropriate for a business.
| Signal | Turnover | Inventory days | What it may indicate |
|---|---|---|---|
| Near your target | In line with your own target | Consistent with your service needs | This comparison is not a performance diagnosis. Review availability, lead times, seasonality, and period-over-period results. |
| Below your target | Below your own target | High | Possible explanations include excess stock, slower demand, or obsolete items. Check item-level sales, age, and availability before deciding. |
| Above your target | Above your own target | Very low | This can reflect fast movement or limited stock coverage. Check stockouts, replenishment lead times, and service levels; the ratio alone cannot identify the cause. |
Inventory Turnover Calculation Examples
Retail boutique (annual)
COGS of ₹2,00,000 with beginning and ending inventory of ₹50,000 each.
Stock is sold and replaced about 4 times a year — roughly every 91 days.
Quarterly example
Quarterly COGS of ₹1,50,000 with average inventory of ₹75,000 and a 90-day period.
Within the quarter, stock turns twice — about 45 days to sell through inventory.
Annual example
Beginning ₹4,90,200 and ending ₹6,09,700 with COGS ₹17,73,000 (scaled example).
Compare with another period only when the dates and calculation basis are consistent.
Compare Inventory Turnover on a Consistent Basis
There is no single target ratio that fits every business. To understand a change in your own stock efficiency, compare periods using the same calculation basis and similar seasonal windows.
Match the period
Use COGS and inventory values from the same dates. A quarterly result is not directly comparable to an annual result.
Keep the numerator consistent
Use COGS for each period when available. Net Sales is only an approximation and should not be mixed into a COGS trend.
Use your own target
Set an internal target based on product mix, seasonality, lead times, and service levels. This calculator does not supply industry averages.
Improve stock efficiency
Strategies to Improve a Low Inventory Turnover Ratio
Inventory sitting unsold ties up working capital, adds storage cost, and risks obsolescence. Use these practical levers when turnover is below your own target.
Markdown slow stock
Identify obsolete or aging SKUs and discount them to free working capital.
Time-limited promotions
Run short campaigns, bundles, or giveaways to move excess inventory quickly.
Social and channel push
Use social promotions or extra marketplace visibility for dead stock.
Review purchase quantities
Tighten reorder points and avoid overbuying based on optimistic forecasts.
Tax write-off options
Where applicable, explore converting unsellable stock into a write-off with your advisor.
Track the trend
Compare turnover and DIO across quarters so you act before cash gets stuck.
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Frequently Asked Questions
Inventory turnover, DIO, COGS fallback, period comparisons, and privacy.
Ready to Act on Your Inventory Data?
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