Perpetual vs. Periodic Inventory System Journal Entries

A. The Sale and Purchase of Products

Perpetual inventory systems show all changes in inventory in the "Inventory" account. Purchase accounts are not used in a perpetual inventory system.

Periodic inventory systems keep the inventory balance at the same value that it was at the beginning of the year. At year end, the inventory balance is adjusted to a physical count. To account for inventory purchases in a periodic inventory system, an account called "Purchases" is used rather than debiting "Inventory".

B. Cost of Goods Sold in a Periodic Inventory System

Perpetual inventory systems record cost of goods sold and keep inventory at its current balance throughout the year. Therefore, there is no need to do a year-end inventory adjustment unless the perpetual records disagree with the inventory count. In addition, a separate cost of goods sold calculation is unnecessary since cost of goods sold is recorded whenever inventory is sold.

The inventory account in a periodic inventory system keeps its beginning balance until the end of period adjustment to the physical inventory count. Therefore, a separate cost of goods sold calculation is necessary. The following calculation shows the calculation for the preceding example.

C. Purchase Returns and Allowances and Purchase Discounts

"Purchases" has a normal debit balance since it replaces the debit to "Inventory". It has two contra accounts known as "Purchase Discounts" (Purch. Disc.) and "Purchase Returns and Allowances" (Purch. R&A) that reduce it to determine "Net Purchases". The balance of these two contra accounts is a credit because "Purchases" is a debit. Remember that contra accounts always have a normal balance that is opposite to what they are contra to. Purchase-type accounts are temporary accounts (i.e., they are closed at year end) and only appear in a periodic inventory system. They simply serve to replace the corresponding inventory portion of an entry that exists in a perpetual inventory system. The following entries illustrate purchase returns and discounts in perpetual and periodic inventory systems:

D. Sales Returns and Allowances and Sales Discounts

Sales has two contra accounts known as "Sales Discounts" (Sales Disc.) and "Sales Returns and Allowances" (Sales R&A) that reduce it. The normal balance for these two contra accounts is a debit. Sales and its contra accounts may appear with either a perpetual or periodic inventory system. The following entries illustrate the accounts in perpetual and periodic inventory systems. The entries assume the gross method.

Sales on the income statement should be shown net of its contra accounts. For example, if a company has $980,000 in sales, $3,400 in sales returns and allowances, and $2,200 in sales discounts; net sales would be $974,400.