Inventory Accounting: Connect Stock Cost to Cost of Goods Sold

Start with one purchase price

Our fictional teaching model starts with no inventory. A shop buys 30 identical display stands at a stated cost of 8 each and pays cash. It later sells 12 of those stands for cash at 15 each. There are no returns, freight, discounts, losses, other purchases or other expenses in this model.

OpenStax distinguishes inventory cost from the cost recognized when goods are sold. Because every unit here has the same supplied cost, no competing purchase layer needs to be selected. That keeps the exercise focused on the stock-to-expense connection.

Trace the purchase and the two parts of the sale

First calculate both prices independently. Buying 30 × 8 adds 240 of inventory cost. Selling 12 × 15 generates revenue of 180, while the cost assigned to those 12 units is 12 × 8 = 96.

Reconcile the remaining stock and explain the margin

The cost check is 96 assigned to sold goods + 144 remaining = 240 available. The physical quantity check is 12 sold + 18 remaining = 30 purchased. Each check uses a consistent unit; neither adds currency and pieces together.

Revenue less the stated COGS is 180 − 96 = 84. That is the gross difference in this simplified exercise, not the shop’s net profit. The model supplies no rent, staff cost or other expense, and the unsold 144 is not additional sales revenue.

See what changes with different purchase costs

If a later batch has a different unit cost, the question becomes which available costs are assigned to the sold units and which remain. FIFO follows the oldest cost layers; a weighted-average calculation pools costs under its specified timing rule. Specific identification traces identified items to their costs.

Those descriptions help choose the next learning exercise. They do not select an accounting policy for a real business. The related tutorials use separate fixtures to show partial FIFO layers and the timing difference between periodic and moving averages.

Give a complete practice explanation

A common error is to reduce inventory by the 180 selling price. That would mix revenue with cost and leave 60 instead of the supported 144. Another is to expense the entire 240 purchase while also retaining all unsold stock as an asset in this model, which counts the same cost twice.