棚卸資産の評価方法と会計処理｜実地棚卸の準備から事後処理まで解説

Inventory refers to assets a company holds for the purpose of selling them, or assets used to produce goods for sale. Proper valuation of this inventory is necessary to calculate a company’s profit and understand its financial health. When inventory is correctly valued at the end of an accounting period, the cost of goods sold for that period is determined, which clarifies the company’s profitability.

This process is a fundamental accounting procedure that ensures the company’s assets are accurately reflected on the balance sheet and that profit is correctly stated on the income statement. For this reason, inventory management and valuation are foundational tasks for business owners and accountants, providing information for key operational decisions.

棚卸資産の種類と範囲

Inventory is classified into several categories based on its form and stage in the production process. The types of inventory a business holds depend on its operations, and identifying them correctly is the first step in proper accounting.

The primary categories of inventory include:

• Merchandise: Goods purchased by retailers or wholesalers that are ready for resale without further processing.
• Finished Goods: Products that have completed the manufacturing process and are ready to be sold to customers.
• Work-in-Process: Partially completed goods that are still in the production cycle. These items are no longer raw materials but are not yet finished goods.
• Raw Materials: The basic materials, parts, and components waiting to be used in the production process.
• Supplies: Consumable items that support production or sales activities, such as cleaning or packaging materials, that are unused at the end of the period.

棚卸資産の評価方法

Inventory is recorded based on the cost principle, meaning it is valued at its acquisition cost. This includes the purchase price plus any other costs required to get the goods ready for sale, such as shipping and handling fees.

To determine the cost of inventory remaining at the end of a period, a company must select a cost flow assumption. Common methods used in the U.S. include First-In, First-Out (FIFO), Last-In, First-Out (LIFO), and the weighted-average method. FIFO assumes the first units purchased are the first ones sold, leaving the newest, most recently purchased items in ending inventory. The weighted-average method smooths out price fluctuations by calculating an average unit cost for all goods available for sale during the period.

An exception to the cost principle requires inventory to be written down if its value falls below its recorded cost. The specific rule depends on the costing method. For companies using FIFO or the weighted-average method, inventory is valued at the lower of cost or net realizable value (NRV). NRV is the estimated selling price minus any costs of completion and disposal. For those using LIFO, the valuation is at the lower of cost or market.

実地棚卸の手順

A physical inventory count is performed at the end of an accounting period to verify the quantity of goods on hand. This process involves physically counting every item and comparing the total to the company’s internal inventory records to identify any differences.

The first step is preparation. This involves scheduling the count for a time with minimal business activity, such as after hours or on a weekend, to ensure an accurate tally. Teams are assigned to specific areas, and sequentially numbered count tags are prepared to track the items being counted and prevent omissions or double-counting.

During the execution phase, teams of two often work together. One person counts the items while the other records the information on a tag that is then attached to the counted inventory. After the count is complete for all areas, all used and unused tags are collected to ensure the process was thorough.

The final step is to reconcile the data. The quantities from the tags are totaled for each item and compared to the book inventory records. If a discrepancy, known as inventory shrinkage, exists, the cause is investigated. Finally, the accounting records are adjusted to match the physical count.

会計処理と財務諸表への影響

The final value of ending inventory is calculated by multiplying the physical count quantity by the unit cost from the chosen valuation method. This figure directly impacts the company’s financial statements, primarily through the calculation of the cost of goods sold (COGS).

COGS is determined using the formula: Beginning Inventory + Purchases – Ending Inventory. This amount is reported as an expense on the income statement and is subtracted from revenue to determine the company’s gross profit. The value of the remaining ending inventory is reported on the balance sheet as a current asset.

If the physical count is less than the book quantity, the difference is an inventory shrinkage loss. This loss is typically included in the cost of goods sold, but if it results from an unusual event like theft, it may be classified as a non-operating expense.

Similarly, if inventory value declines and a write-down is necessary, the resulting inventory valuation loss is also usually treated as part of COGS. Under U.S. Generally Accepted Accounting Principles (GAAP), once inventory has been written down, its new lower value becomes its cost basis. This write-down cannot be reversed in future periods, even if the inventory’s market value recovers.