Calculator input
Example data table
| Period | Opening Inventory | Closing Inventory | COGS | Average Inventory | Turnover Ratio | Turnover % | Days in Inventory |
|---|---|---|---|---|---|---|---|
| Q1 | 50,000 | 42,000 | 140,000 | 46,000 | 3.04 | 304.35% | 29.60 |
| Q2 | 42,000 | 47,500 | 160,000 | 44,750 | 3.58 | 357.54% | 25.14 |
| Q3 | 47,500 | 39,000 | 150,000 | 43,250 | 3.47 | 346.82% | 25.95 |
| Q4 | 39,000 | 36,000 | 170,000 | 37,500 | 4.53 | 453.33% | 19.87 |
Formula used
Average Inventory = (Opening Inventory + Closing Inventory) ÷ 2
Adjusted COGS = COGS × (1 + Shrinkage Adjustment ÷ 100)
Inventory Turnover Ratio = Adjusted COGS ÷ Average Inventory
Inventory Turnover Percentage = Inventory Turnover Ratio × 100
Days in Inventory = Period Days ÷ Inventory Turnover Ratio
Sell-Through Percentage = Adjusted COGS ÷ (Opening Inventory + Purchases) × 100
Annualized Turnover Ratio = Inventory Turnover Ratio × (365 ÷ Period Days)
How to use this calculator
- Enter opening inventory, closing inventory, and cost of goods sold.
- Add period days to match your analysis window.
- Optionally enter net sales, purchases, a custom average, shrinkage adjustment, and target turnover ratio.
- Click the calculate button to show turnover percentage and all supporting metrics.
- Review the graph, metrics table, and performance band for interpretation.
- Download the result summary as CSV or PDF for reporting.
FAQs
1. What does inventory turnover percentage show?
It converts the turnover ratio into percentage form. A higher value means stock is sold and replaced faster relative to average inventory held during the chosen period.
2. Why is turnover ratio often preferred in reports?
The ratio is the standard accounting measure. The percentage version is useful when you want a quick visual comparison or a more intuitive performance presentation.
3. What is a good inventory turnover value?
It depends on the industry, margin structure, and product life cycle. Grocery businesses often run higher turns than luxury, seasonal, or slow-moving industrial stock.
4. Why does the calculator ask for period days?
Period days help calculate days in inventory and annualized turnover. This makes monthly, quarterly, and yearly analyses comparable on a common basis.
5. When should I use custom average inventory?
Use it when you have weighted monthly averages, audited values, or a more precise internal estimate than the simple opening-and-closing average.
6. What does shrinkage adjustment do?
It adjusts cost of goods sold for loss, damage, theft, or stock corrections. This helps you reflect operational reality before interpreting turnover performance.
7. Why might days in inventory matter more than turnover percentage?
Days in inventory directly shows how long goods stay in stock. Many planners find this easier for replenishment, storage, and working-capital decisions.
8. Can this calculator replace full inventory analysis?
No. It is a strong screening tool, but full analysis should also consider stockouts, lead times, demand volatility, seasonality, service levels, and product mix.