Why Should You Track Days of Inventory Supply?

Last Updated on June 29, 2023 by Lauren Beck

In the realm of business, the art of inventory management holds tremendous power. As a seasoned entrepreneur, I’ve learned that tracking the days of inventory supply is the key to success. 

Join me on this journey as we unveil the reasons behind this vital practice and discover how it can optimize your business operations.

Why Should You Track Days of Inventory Supply?

Tracking days of inventory supply is essential for effective inventory management. 

It helps businesses understand how long their inventory can sustain sales, identify potential issues like excess stock or slow-moving items, avoid stockouts, minimize costs, optimize operations, and make informed decisions for better business performance.

What Is Days Sales in Inventory?

Days Sales in Inventory (DSI) measures how long your inventory can support your sales activity. 

It calculates the number of days it would take to sell your entire inventory based on your average daily sales. 

DSI helps you understand the efficiency of your inventory management and identify potential issues, such as excess stock or slow-moving items.

How to Calculate Inventory Days On Hand:

  • Determine Average Daily Sales: Calculate the average daily sales by dividing the total sales over a given period by the number of days in that period.
  • Calculate Average Inventory: Calculate the average inventory by adding the beginning inventory and ending inventory for a specific period and dividing the sum by 2.
  • Calculate Days Sales in Inventory: Divide the average inventory by the average daily sales to get the number of days your inventory can sustain sales.

What Are the Implications of Low Days of Inventory on Hand?

  • Stockouts: Low days of inventory on hand increase the risk of running out of stock, leading to missed sales opportunities and dissatisfied customers.
  • Increased Costs: Urgent replenishment orders to combat low inventory can lead to higher costs, including expedited shipping or higher purchase prices.
  • Operational Disruptions: Insufficient inventory levels can disrupt production schedules, impacting overall operations and potentially causing delays in fulfilling customer orders.

What Are the Average Days of Inventory on Hand?

Man Checking Inventory

Average days of inventory on hand can vary across industries, product types, and business models. Some industries, like fashion or technology, may have shorter inventory turnover cycles, resulting in lower average days of inventory on hand. 

On the other hand, industries with longer production lead times or specialized products may have higher average days of inventory on hand. 

It’s important to compare your days of inventory with industry benchmarks and your own historical data to assess your performance.

How to Avoid Slow-Moving Inventory?

  • Demand Forecasting: Use historical sales data, market trends, and customer insights to forecast demand accurately. This helps align inventory levels with expected sales and reduces the risk of excess inventory or stockouts.
  • Effective Inventory Management Systems: Implement inventory management systems that provide real-time visibility into stock levels, automate replenishment processes, and enable data-driven decision-making [1].
  • Promotions and Marketing Strategies: Develop strategies to promote slow-moving inventory through targeted marketing campaigns, discounts, or bundling with popular items.
  • Supplier Collaboration: Work closely with suppliers to establish efficient order and delivery processes, ensuring optimal inventory levels while minimizing lead times.


In the intricate dance of business, the days of inventory supply serve as a compass, guiding you toward operational excellence. 

Tracking this vital metric can uncover insights into your inventory efficiency, anticipate challenges, and make informed decisions. Embrace the power of inventory management, avoid costly stockouts or excess stock, and foster a streamlined operation that keeps customers satisfied and your bottom line thriving. 

So, take the reins of your inventory, track those days of supply, and watch your business flourish in the realm of efficient and profitable operations.


Lauren Beck
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