Periodic Inventory System: Definition, Examples, and Implementation


The periodic inventory system is an accounting method that requires physical inventory counts at specific intervals, often used by small businesses. This article explores the concept, its pros and cons, and how it compares to perpetual inventory. You’ll also find insights into when to use it, advantages, and its limitations.

Understanding the Periodic Inventory System

The periodic inventory system is an accounting approach that plays a crucial role in a company’s financial reporting. In this method, a physical count of the inventory is conducted at predetermined intervals, such as the end of a month, quarter, or fiscal year. This system offers a different approach to managing inventory compared to the more advanced perpetual inventory system.

How periodic inventory works

In the periodic inventory system, a company takes inventory at the beginning of a specific accounting period, adds new inventory purchases made during that period, and then deducts ending inventory. This calculation helps derive the cost of goods sold (COGS). The periodic inventory system is often the go-to method for small businesses, particularly those with limited resources and staff to perform frequent inventory counts.

Small companies, especially those with low sales volumes, find the periodic inventory system both easier and more cost-effective to implement. Unlike the perpetual inventory system that continuously updates inventory levels, the periodic system only tracks inventory during specific periods.

Pros and cons of periodic inventory

Weigh the risks and benefits

Here is a list of the benefits and drawbacks to consider.

  • Cost-effective for small businesses
  • Easy to implement
  • Doesn’t require advanced software
  • Potential for human error
  • Difficulties detecting defects or theft
  • Possible need to shut down operations for inventory count

The advantages of periodic inventory are evident, especially for small businesses. It’s a cost-effective method that doesn’t necessitate sophisticated software or extensive human resources. However, there are disadvantages as well. Human error, difficulties in identifying defects or theft, and the occasional need to halt operations for inventory counts are among the potential drawbacks.

Periodic inventory vs. perpetual inventory

To fully comprehend the periodic inventory system, it’s essential to compare it to the perpetual inventory system. The differences between the two are significant, and they cater to different business needs.

Under the periodic inventory system, a company only knows its inventory levels and COGS after the physical count is completed, which can be suitable for businesses with a limited number of stock-keeping units (SKUs) in a slow-moving market.

On the other hand, the perpetual inventory system continuously updates the inventory asset ledger in a company’s database, providing instant insights into inventory levels and COGS. This system is favored for its real-time data and the ability to track individual inventory items efficiently.

Example of periodic inventory

To illustrate how periodic inventory works, consider the following example:

Let’s assume a company’s inventory is valued at $500,000 on January 1. Over the course of three months, the company purchases $250,000 worth of inventory. Following a physical inventory count on March 31, the inventory is determined to be worth $400,000. This $400,000 becomes the beginning inventory for the next quarter, and the COGS for the first quarter is calculated as $350,000 ($500,000 beginning + $250,000 purchases – $400,000 ending).

However, it’s worth noting that periodic inventory can lead to time discrepancies, making it essential for management to decide how often inventory counts should be conducted to align with business needs effectively.

Advantages and limitations of a periodic inventory system

The periodic inventory system is a favored choice for businesses with specific characteristics. Let’s delve deeper into the advantages and limitations of this system.

Advantages of periodic inventory system

The periodic inventory system is commonly used by businesses that sell a small quantity of goods during an accounting period. These companies often find it beneficial to use this system because it is easy to implement and cost-effective, as it doesn’t require any fancy software.

Limitations of periodic inventory system

One of the main limitations of the periodic inventory system is that it may not readily identify shrinkage or discrepancies between actual stock and recorded inventory levels. Since inventory counts occur only at the beginning and end of the reporting period, any theft, damage, or unknown causes of loss might go unnoticed.

When to use a periodic inventory system

Determining when to use the periodic inventory system depends on the nature of your business and its specific requirements. Companies would typically opt for the periodic inventory system if they:

– Sell a small quantity of goods during an accounting period.
– Don’t have enough employees to conduct a perpetual inventory count.
– Find it cost-effective and straightforward for their operations.

This system is often favored by small businesses, art dealers, and car dealers, as it aligns with their characteristics and needs.

Implementing periodic inventory: a step-by-step guide

Suppose you’re considering adopting the periodic inventory system for your business. In that case, it’s crucial to understand how to implement it effectively. Let’s explore a step-by-step guide to help you make the most of this accounting method.

1. Determine your counting frequency

The first step is to decide how often you’ll conduct physical inventory counts. Typically, businesses choose to do this on a monthly, quarterly, or annual basis. The choice should align with your business needs, ensuring that you have an accurate view of your inventory.

2. Prepare for the inventory count

Before you start counting, it’s essential to make preparations. This includes allocating the necessary resources, such as personnel and equipment, and setting up a controlled environment to minimize disruptions during the count.

3. Conduct the physical count

During the designated counting period, your team will physically count all the inventory on hand. This involves examining each item to ensure accuracy. Take your time and be thorough in this process.

4. Record your findings

As the physical count progresses, record the quantities of each item and their values. Modern technology, such as inventory management software, can streamline this step and reduce the chances of human error.

5. Calculate the cost of goods sold (COGS)

Once the physical count is complete, you can calculate the

COGS. This is done by comparing the beginning inventory value to the ending inventory value and adding the purchases made during the accounting period.

Real-life examples of periodic inventory implementation

To illustrate how different businesses apply the periodic inventory system, here are some real-life examples:

Retro record store

A small retro record store with limited daily sales decides to use the periodic inventory system. Since they have a small volume of inventory and don’t want to invest in advanced software, they opt for a monthly counting frequency. This allows them to keep track of their rare vinyl records effectively.

Art gallery

An art gallery that deals in unique, high-value pieces also chooses the periodic inventory system. They conduct quarterly physical counts to accurately assess the value of their artworks. For the art gallery, the ease of implementation and cost-effectiveness make it a practical choice.

Local hardware store

A local hardware store with a wide range of products uses the periodic inventory system due to its simplicity. They conduct annual inventory counts, making it a manageable task for their small team. While it may not provide real-time data, it meets their needs for inventory management.

Advanced inventory management: combining periodic and perpetual systems

In some cases, businesses may benefit from a hybrid approach that combines both periodic and perpetual inventory systems. Here’s how it can work:

1. Utilize perpetual for high-value items

For high-value, fast-moving items, such as electronics or luxury goods, consider using a perpetual inventory system. This real-time tracking ensures you have accurate data for your most crucial assets.

2. Apply periodic for low-volume items

For items with low sales volume, periodic inventory is still a practical choice. It saves resources and minimizes the need for frequent counts, making it cost-effective.

3. Integrate technology

To streamline the process and reduce human error, use inventory management software that can handle both periodic and perpetual tracking. This integration ensures you have accurate data for decision-making.


In conclusion, the periodic inventory system is a valuable accounting method, particularly for small businesses and those with limited resources for frequent inventory counts. It offers both advantages and limitations, making it suitable for specific business scenarios. Understanding when and how to use this system is crucial for effective inventory management and financial reporting.

Frequently Asked Question

What is the primary difference between the periodic and perpetual inventory systems?

The primary difference lies in how inventory is tracked. In the periodic inventory system, inventory counts are done at specific intervals, while the perpetual system continuously updates inventory. This impacts real-time insights, cost tracking, and resource requirements.

Is the periodic inventory system suitable for all businesses?

No, the suitability depends on the nature and needs of the business. Small businesses and those with low sales volumes often find it cost-effective, while larger businesses with higher inventory turnover may prefer the perpetual system for its real-time data.

What are the advantages of using the periodic inventory system?

Advantages include cost-effectiveness and simplicity of implementation. It’s especially beneficial for businesses with limited resources. It doesn’t require advanced software and can be a practical choice for certain scenarios.

How can I identify inventory shrinkage with the periodic inventory system?

Identifying shrinkage can be challenging with periodic inventory since it takes counts only at the beginning and end of the reporting period. Any discrepancies between actual stock and recorded levels might require additional investigations to uncover the causes.

When should I consider a combination of periodic and perpetual inventory systems?

A combination can be useful when you have a mix of high-value and low-volume items. Use perpetual for high-value, fast-moving items and periodic for low-volume goods. Integrating technology to handle both methods ensures you have accurate data for decision-making.

Key takeaways

  • The periodic inventory system requires physical inventory counts at specific intervals, making it suitable for small businesses.
  • Advantages include cost-effectiveness and simplicity of implementation, while limitations involve the potential for unnoticed inventory discrepancies.
  • Choosing between periodic and perpetual inventory systems depends on the nature of your business and its specific requirements.
View article sources
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  4. Records Inventory – National archive