Days Inventory Outstanding: Calculation, formulas & strategies

In the daily operations of a small to mid-sized business (SMB), one metric stands out as a critical indicator for management: Days Inventory Outstanding.

More than just a financial term, it offers valuable perception into a business’s operational efficiency.

Consider the scenario of a warehouse stocked with inventory while cashflow remains tight.

This is where DIO becomes essential. It measures the time it takes for your products to move from the shelf to being sold.

A high rate may indicate that your capital is tied up in an unsold stockpile, potentially hindering revenue generation.

In this article, we’ll delve into the concept of Days Inventory Outstanding and share the formula used to calculate it. We’ll also bring the ideal ratio and the roadmap to achieve it.

This is a must-read for managers of SMBs who are committed to optimizing operations and boosting their bottom line.

What is Days Inventory Outstanding?

Days Inventory Outstanding is a financial metric that measures the average number of days a company takes to convert its inventory into sales. This ratio serves as an indicator of the efficiency of supply turnover within a specified timeframe.

A lower DIO value indicates quicker inventory turnover, signaling effective management and a reduced risk of obsolescence.

Conversely, a higher one suggests that reserve is held for longer periods, potentially leading to increased storage costs and tied-up capital.

Also known as days sales inventory (DSI), it is a key component of the Cash Conversion Cycle (CCC).

This ratio, in turn, measures how quickly a company can convert its investment in inventory into cash.

The CCC is calculated as:

Where:

DSO represents Days Sales Outstanding

DPO stands for Days Payable Outstanding

How to calculate DIO? 

The formula for Days Inventory Outstanding is:

Where:

• Average inventory is the average value of the inventory at the start and end of the period. It is computed as: Average Inventory = Beginning inventory + Ending inventory / 2
• Cost of Goods Sold (COGS) represents the total expenditure associated with the goods that were sold during the period
• 365 is used to convert the turnover ratio into days. This number can be adjusted accordingly for quarterly or monthly periods to reflect the specific time frame under consideration.
• This conversion allows us to understand the metric in terms of days, providing a more intuitive understanding of how long, on average, inventory items remain unsold

Consider TechMart, an electronics retailer specializing in smartphones, laptops, and tablets. They currently hold an inventory valued at $500,000, and their annual Cost of Goods Sold (COGS) amounts to $1,825,000. 

Firstly, we compute the average daily COGS ($1,825,000) divided by 365 days, which equals $5,000 per day.

Next, we calculate the metric using the formula:

DIO: ($500.000 / $1.825.000) x 365 = 100 days

This calculation reveals that TechMart takes an average of 100 days to sell its entire inventory.

What implications does it have?

If the industry average ratio is 60 days, TechMart’s inventory turnover appears to be slower than its competitors.

This could suggest several potential issues:

• Overstocking: the SMB may be holding more inventory than necessary
• Slow-moving products: some products may not be selling as quickly as expected
• Potential for obsolescence: given the rapid pace of technological advancements, electronics can quickly become outdated, increasing the risk of obsolescence

Therefore, it would be beneficial for TechMart to strive towards reducing its DSI. This would enhance cashflow, decrease storage costs, and minimize the risk of inventory becoming obsolete.

Why is Days Sales Inventory so important?

The metric is far more than a mere numerical value. It serves as a lens through which the management can scrutinize essential aspects of a company’s performance:

1. Operational efficiency

A lower scale reflects efficient inventory management and a faster sales process.

Companies with a lower DSI are typically more agile, responding quickly to market demands.

2. Cashflow management

Efficient supply turnover, indicated by a lower DIO, frees up cash that can be reinvested into other areas of the business.

In contrast, a high level can tie up capital in unsold inventory, potentially affecting liquidity and the overall financial health of the company.

3. Sales performance

DSI serves as an indicator of sales effectiveness.

An increasing index might hint at issues with demand forecasting or sales processes, while a decreasing number often signals strong sales and efficient inventory turnover.

4. Cost management

A high DIO can result in greater holding costs and an increased risk of inventory obsolescence.

On the other hand, effective management, reflected in a lower value, helps minimize these risks and optimize storage costs.

What constitutes a healthy DIO?

There isn’t exactly a standard for an appropriate measurement, as this can vary according to business models and even industries.

However, we can provide an overview of the levels that are considered healthy for the following niches:

• Retail sector: retail businesses typically aim for a lower rate, often within the 30 to 60-day range. This reflects a rapid inventory turnover and strong sales performance
• Manufacturing sector: manufacturers often have a higher number, generally between 60 to 120 days, as shown in a data collection by Ready Ratios. This is due to the longer production cycles and lead times inherent in the manufacturing process
• Luxury goods: companies dealing in high-end products may experience a greater proportion, potentially exceeding 120 days. This is attributed to slower sales cycles and higher inventory costs associated with luxury items

While days sales inventory varies by industry and business model, it is crucial to maintain it near optimal levels for the company’s specific niche. A

lower ratio typically signifies efficient inventory management and rapid sales.

However, an excessively low number can result in insufficient stock, leading to lost sales and revenue.

Conversely, a high ratio indicates overstocking, inefficient management, and potential liquidity issues.

Determining what constitutes a healthy metric involves a comparative analysis of your company’s numbers against industry benchmarks and historical performance data. So, when assessing your metric, consider these critical questions:

1. Is your DIO stable, increasing, or decreasing? A lowering ratio might indicate improved efficiency, while an increasing one could signal potential issues
2. How do your numbers stack up against competitors? Industry benchmarks provide valuable context and help you gauge your performance against others

Read more: How can invoice financing handle inventory and suppliers? 

Strategies to improve your inventory management

Achieving an optimal rate requires balancing inventory levels with sales efficiency.

Here are some expert strategies:

1. Enhance demand forecasting

By enhancing the precision of demand prediction, you can mitigate the need for excess inventory.

This alignment of stock levels with anticipated sales reduces the risk of overstocking or understocking.

2. Improve sales processes

Streamlining the sales cycle can shorten the time it takes to convert inventory into sales, thus lowering the coefficient.

Building strong supplier relationships can also lead to more reliable delivery schedules and better supply chain visibility, further optimizing backlog turnover.

3. Adopt Just-in-Time (JIT) inventory practices

This strategy reduces the need for large reserve holdings by ensuring materials or products arrive just as they are needed.

This approach minimizes inventory possession time, directly reducing DIO and freeing up capital.

4. Clear out slow-moving stock

Regularly review inventory and take action on items that are moving slowly. Offering discounts or promotions can help clear out aging stock, freeing up space and reducing the risk of obsolescence.

5. Leverage data analytics

Utilize data analytics and machine learning to uncover patterns and trends in management.

These insights can inform more effective strategies, such as adjusting inventory levels based on real-time data and predictive analytics.

6. Optimize inventory levels

Experiment with supply levels by considering factors like lead times, safety stock, and seasonal demand fluctuations. The goal is to strike a balance that ensures product availability while minimizing excess reserve.

Staying informed about industry trends and best practices is essential for overcoming inventory management challenges.

Comparing your levels to industry standards allows stakeholders to assess whether the company is managing effectively or if adjustments are needed to remain competitive.

Unlock the hidden value in your inventory. Learn how to turn excess stock into growth capital with inventory financing. 

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