Cash conversion cycle

DIO Calculator (Days Inventory Outstanding)

Find out how many days your stock takes to turn over, how much capital you have tied up in the warehouse and how it compares with your sector benchmark.

Calculate my DIO

Enter your balance-sheet and income-statement figures to get your DIO, the capital tied up and inventory turnover.

Average value of stock in the warehouse. Use the average of the start and end of the year.

Total cost of goods and materials consumed in the period.

days
Capital tied up in stock
average inventory value
Inventory turnover
times per year

What is DIO?

DIO (Days Inventory Outstanding), also known as the average inventory period, measures the average number of days a company takes to sell its stock. The lower the DIO, the faster stock is converted into sales, and the less capital sits tied up in the warehouse.

A high DIO means the company has money parked in goods that are not generating revenue. That tied-up capital can put pressure on working capital and force the business to turn to external financing for day-to-day operations.

DIO formula DIO = (Average Inventory ÷ COGS) × Period

Example: Inventory = €150,000 | Annual COGS = €900,000
DIO = (150,000 ÷ 900,000) × 365 = 61 days

The average inventory is obtained by adding the stock at the start and end of the year and dividing by two. COGS appears in the income statement under "Cost of goods sold and materials consumed".

Sector benchmarks — typical DIO

The ideal DIO varies widely depending on the line of business. A technology company can hold almost no stock, whereas a manufacturer needs a considerable safety-stock buffer.

SectorTypical DIOAnnual turnoverRating
Technology / Services5–20 days18–73×A
Retail30–60 days6–12×B
Wholesale30–75 days5–12×C
Manufacturing45–90 days4–8×C
Construction60–120 days3–6×D

Indicative values based on Banco de Portugal data and European sector studies. The ideal DIO for each company also depends on its supply chain and safety-stock policy.

How to free up the capital tied up in stock

A high DIO does not necessarily mean poor management — it can be a sector requirement or the result of seasonality. But there are ways to reduce tied-up capital without compromising your ability to serve customers.

Just-in-time ordering

Order based on real sales history rather than optimistic projections. Reduce minimum order quantities by negotiating with suppliers — even if the unit cost is slightly higher, the total cost of holding stock falls.

Calculate the impact on working capital →

Confirming with suppliers

If the DIO is high out of operational necessity, offset it with longer supplier payment terms via confirming. The supplier is paid on term (or pulls it forward with a discount); the company keeps the stock it needs without immediate treasury pressure.

Learn more about confirming →

Clearing obsolete stock

Identify items with no turnover for more than 6–12 months. Offer discounts, return them to the supplier or sell them off — any value recovered beats keeping capital idle. Obsolete stock also takes up space and generates storage costs.

Calculate DPO, payment term →

Frequently asked questions

What is DIO and how is it calculated?
DIO (Days Inventory Outstanding) measures the average number of days stock takes to be sold. It is calculated as: DIO = (Average Inventory ÷ COGS) × Period. The average inventory is the average of stock at the start and end of the period. COGS (cost of goods sold and materials consumed) appears in the income statement. A DIO of 60 days means that, on average, stock is renewed every 60 days.
What is inventory turnover and what is the ideal value?
Inventory turnover indicates how many times per year stock is fully renewed. It is calculated as COGS ÷ Average Inventory. A turnover of 6× means stock is renewed 6 times a year (equivalent to a DIO of 61 days). There is no universally ideal value: food retail can reach 30× or more; heavy industry may be 4–6×. What matters is to compare with your sector benchmark and track the trend over time.
How can I reduce excess stock without hurting sales?
The most effective approach combines three strategies: 1) ABC analysis — the 20% of items that account for 80% of sales justify a robust safety stock; the remaining 80% should be kept to a minimum; 2) just-in-time ordering based on real historical data, not estimates; 3) periodic review of items with no turnover for more than 90 days, since any clearance generates immediate liquidity. In addition, using confirming to extend supplier payment terms reduces treasury pressure without forcing an operational cut in the stock you need.
What is the relationship between DIO and the company's cash flow?
DIO is one of the three components of the cash conversion cycle: CCC = DSO + DIO − DPO. Every day of DIO represents capital locked in goods that have not yet been sold. For example, a company with a DIO of 90 days and COGS of €1,200,000/year has €300,000 permanently tied up in stock. Reducing DIO by 30 days would free up €100,000 in liquidity — capital that could cut debt, fund growth or improve working capital.

Offset a high DIO with Confirming

If your stock demands tied-up capital, confirming extends supplier payment terms and factoring advances receivables, freeing the liquidity that inventory holds back — without creating new debt.