Question

What is the difference between perpetual and periodic inventory systems? Give examples of the type of businesses that are likely to use (i) perpetual inventory system and (ii periodic inventory system.

Answer 1

The periodic system relies upon an occasional physical count of the inventory to determine the ending inventory balance and the cost of goods sold, while the perpetual system keeps continual track of inventory balances. There are a number of other differences between the two systems, which are as follows:

Accounts. Under the perpetual system, there are continual updates to either the general ledger or inventory ledger as inventory-related transactions occur. Conversely, under a periodic inventory system, there is no cost of goods sold account entry at all in an accounting period until such time as there is a physical count, which is then used to derive the cost of goods sold.

Cost of goods sold. Under the perpetual system, there are continual updates to the cost of goods sold account as each sale is made. Conversely, under the periodic inventory system, the cost of goods sold is calculated in a lump sum at the end of the accounting period, by adding total purchases to the beginning inventory and subtracting ending inventory. In the latter case, this means it can be difficult to obtain a precise cost of goods sold figure prior to the end of the accounting period.

Cycle counting. It is impossible to use cycle counting under a periodic inventory system, since there is no way to obtain accurate inventory counts in real time (which are used as a baseline for cycle counts).

Transaction investigations. It is nearly impossible to track through the accounting records under a periodic inventory system to determine why an inventory-related error of any kind occurred, since the information is aggregated at a very high level. Conversely, such investigations are much easier in a perpetual inventory system, where all transactions are available in detail at the individual unit level.

# Perpetual inventory is often used in large businesses whereas simpler systems like periodic inventory are generally seen in smaller businesses. Perpetual inventory systems are also used when a company has more than one location or when a business carries expensive goods such as an electronics company or jewelry store

# Business types using the periodic inventory system include companies that sell relatively few inventory units each month such as art galleries and car dealerships.