Calculate days inventory outstanding, inventory turnover, holding costs, and compare against industry benchmarks. Includes sensitivity analysis and efficiency metrics.
Days Inventory Outstanding (DIO) measures the average number of days a company holds inventory before selling it. It's one of the three components of the Cash Conversion Cycle and a critical metric for working capital management, supply chain efficiency, and cash flow optimization. A lower DIO generally means faster inventory turnover and less capital tied up in unsold stock.
DIO varies enormously by industry. Grocery stores turn inventory in 5-15 days, while luxury goods companies may hold stock for 60-120 days. What matters is your trend and your performance relative to peers. A rising DIO might signal demand problems, overordering, or product obsolescence. A falling DIO could indicate improved efficiency, but if too aggressive, might mean frequent stockouts and lost sales.
This calculator computes DIO from your COGS and inventory data, shows inventory turnover, estimates annual holding costs (typically 25% of inventory value), and benchmarks your performance against industry standards. The sensitivity table shows exactly how inventory level changes affect your efficiency metrics.
Monitoring DIO helps you spot inventory problems early, reduce holding costs, and free up cash for growth. This calculator gives you the metrics, benchmarks, and sensitivity analysis needed to optimize inventory levels and improve the cash conversion cycle.
Average Inventory = (Beginning + Ending Inventory) ÷ 2 Daily COGS = Total COGS ÷ Days in Period DIO = Average Inventory ÷ Daily COGS Inventory Turnover = COGS ÷ Average Inventory Estimated Holding Cost = Average Inventory × 25%
Result: DIO 50.2 days — turnover 7.3×
Average inventory = ($150K + $180K) ÷ 2 = $165K. Daily COGS = $1.2M ÷ 365 = $3,288. DIO = $165K ÷ $3,288 = 50.2 days. Turnover = $1.2M ÷ $165K = 7.3× per year. Estimated holding cost = $165K × 25% = $41,250/year.
Use COGS, not revenue, when estimating DIO, and compare like periods when seasonality matters. A lower number is not always better if it creates stockouts or missed sales.
The most common errors are using ending inventory only, comparing mismatched periods, or ignoring obsolete stock. For a cleaner working-capital picture, review DIO alongside DSO and DPO.
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This worksheet calculates average inventory from the beginning and ending balances, divides cost of goods sold by the selected number of days to estimate daily COGS, and then computes DIO as `average inventory / daily COGS`. It also reports inventory turnover, gross margin, inventory-to-revenue ratio, and a holding-cost estimate using a flat 25% carrying-cost assumption.
The formula-driven outputs use the entered inventory, COGS, revenue, and period values directly. The industry ranges and 25% holding-cost assumption are reference aids only; they are not authoritative regulatory thresholds or company-specific cost studies.
It depends entirely on your industry. Under 30 days is excellent for retail/e-commerce, 30-60 is average for most businesses, and industrial/equipment companies may reasonably be 90-180 days. Always benchmark against your specific industry and competitors.
CCC = DIO + DSO − DPO. DIO measures inventory days, DSO measures receivables days, and DPO measures payables days. A lower CCC means faster conversion of inventory to cash. Reducing DIO is often the most impactful lever.
Rising DIO can signal: slowing demand, overordering/overstocking, product obsolescence, seasonal buildup, or supply chain issues. It means more cash is tied up in inventory for longer, which hurts liquidity.
Industry research suggests 20-30% of inventory value annually, including: warehousing/rent (5-10%), insurance (1-3%), shrinkage/damage (2-5%), opportunity cost (5-10%), and obsolescence (3-8%). We use 25% as a standard estimate.
Always use COGS. Inventory is carried at cost, not at selling price. Using revenue would understate DIO because it includes your markup. COGS provides an apples-to-apples comparison with inventory values.
Implement just-in-time (JIT) inventory, use demand forecasting to order more accurately, run promotions on slow-moving stock, reduce supplier lead times, improve demand planning, and regularly review and liquidate obsolete items. Focus first on the SKUs that tie up the most cash.