In accounting, Cost of Goods Sold is an expense account that lives on the income statement. It’s a temporary account, meaning its balance resets to zero at the end of each accounting period, and it captures the direct costs of producing or acquiring the goods a business sold during that period. Revenue minus COGS equals gross profit, which is why COGS sits directly beneath the revenue line rather than down with general operating expenses.
Why COGS Is Classified as an Expense Account
COGS behaves like other expense accounts in one important way: it accumulates costs over a reporting period and then closes out at period end. Unlike inventory, which is a permanent asset account that carries its balance forward, COGS starts each new period at zero and builds up as sales occur.
Some accounting educators describe COGS as a “contra-revenue” account because it offsets revenue rather than sitting alongside general operating expenses like rent or marketing. In practice, most accounting systems treat it as a temporary expense account. Whatever label your chart of accounts applies, the mechanics are the same: COGS flows through the income statement, not the balance sheet.
Where COGS Appears on the Income Statement
COGS is the first expense line deducted from revenue. That placement is deliberate. Subtracting it from revenue produces gross profit, which isolates production efficiency from overhead management. Everything else — administrative salaries, office rent, marketing, insurance, legal fees — falls below gross profit as an operating expense.
A quick example makes the structure concrete. If a company brings in $1 million in revenue and reports $600,000 in COGS, gross profit is $400,000, a 40% margin. That $400,000 is the pool available to cover every non-production cost before the business earns a net profit. When gross margins shrink over time, the cause is almost always inside COGS: rising material costs, higher production wages, or prices that haven’t kept up.
The Link Between Inventory and COGS
The account type question gets clearer once you see how a cost moves through the books. When a business buys or produces inventory, the cost is recorded as an asset on the balance sheet. The money hasn’t been “spent” in accounting terms; it’s been converted from cash into another kind of asset. Nothing hits the income statement yet.
The moment that inventory is sold, its cost transfers off the balance sheet and lands in COGS on the income statement. Inventory (asset) goes down, COGS (expense) goes up by the same amount. That transfer is the whole reason COGS exists as an account: it’s the mechanism for recognizing inventory cost as an expense in the same period the related revenue is recognized.
How COGS Gets Recorded in the Books
The journal entries that populate the COGS account depend on which inventory system a business uses.
Perpetual System
A perpetual system updates inventory in real time. Every sale triggers two entries. The first records the revenue side: cash or accounts receivable is debited, sales revenue is credited. The second records the cost side: COGS is debited and inventory is credited. Sell a product that cost $40 to acquire, and $40 debits COGS while $40 credits inventory. The COGS balance is always current, so financial statements can be pulled at any point without waiting for a physical count.
Periodic System
A periodic system leaves the inventory account balance untouched during the period and doesn’t debit COGS on each sale. At period end, someone physically counts what’s left. COGS is then calculated using beginning inventory plus net purchases minus ending inventory, and the result is recorded through an adjusting entry before financial statements are prepared. The method is simpler and less expensive to run, which is why smaller businesses with lower transaction volumes tend to use it. The trade-off is no real-time visibility into cost of sales until the count is done.
Whichever system a business uses, the ending balance in COGS closes out to retained earnings (or to an income summary account first, in more formal closing procedures) when the books are closed for the period. That closing step is what makes COGS a temporary account.
What Belongs Inside the Account
Not every business cost belongs in COGS. Only costs directly tied to producing or purchasing the goods sold qualify. For a manufacturer, that means raw materials, factory labor (both production workers and support staff whose work is necessary to the manufacturing process), and production overhead such as factory rent, utilities, equipment depreciation, and maintenance. For a retailer or wholesaler, it’s mainly the purchase price of merchandise plus inbound shipping.
The IRS groups these into specific categories for tax reporting:
- Materials and supplies: raw materials, parts, chemicals, hardware, and any supplies physically consumed in production.
- Direct labor: wages paid to employees who work on the product being manufactured, including a proportional share of wages for employees who split time between production and other duties.
- Indirect labor: wages for employees who perform general factory functions necessary to the manufacturing process but who don’t work directly on the product.
- Freight-in: shipping costs to bring raw materials or merchandise to your location.
- Overhead: factory rent, heat, light, power, insurance, depreciation, taxes, and maintenance tied to the production operation.
Containers and packaging that are part of the finished product also belong in COGS. Packaging used solely for shipping to customers, however, is a selling expense.1Internal Revenue Service. Publication 334 – Tax Guide for Small Business
What Does Not Belong
Costs that keep the business running but aren’t tied to production or purchasing inventory are operating expenses, not COGS. Administrative salaries, office rent, marketing, legal fees, and accounting costs all fall into that category. So does freight-out, the cost of shipping finished goods to customers, which is a selling expense. Mixing these up inflates COGS, understates operating expenses, and makes gross margins look worse than they are while hiding high overhead.
Service Businesses: No COGS Account
Businesses that sell services rather than physical goods don’t maintain a COGS account. A law firm, consulting practice, or painting contractor has no inventory to convert into expense. These businesses use a “cost of sales” or “cost of revenue” line instead, which captures the direct costs of delivering the service, such as wages for billable staff and travel expenses incurred while serving clients. The IRS specifically notes that its COGS rules do not apply to personal service businesses unless they also sell materials or supplies alongside their services.1Internal Revenue Service. Publication 334 – Tax Guide for Small Business
How COGS Is Treated on Tax Returns
On a tax return, COGS is technically not a “deduction” in the same way advertising or office supplies are. It’s an offset against revenue used to determine gross income. The distinction rarely matters for the math, but it does change where the number gets reported.
Sole proprietors and single-member LLCs report COGS on Part III of Schedule C (Form 1040). That section walks through beginning inventory, purchases, cost of labor, materials and supplies, other costs, and ending inventory line by line.2Internal Revenue Service. 2025 Instructions for Schedule C (Form 1040) Corporations, S corporations, and partnerships that claim a COGS deduction must complete and attach Form 1125-A to their entity returns (Form 1120, 1120S, or 1065).3Internal Revenue Service. About Form 1125-A, Cost of Goods Sold
Whatever the return, the underlying account behavior on the books stays the same: COGS is a temporary expense account that captures inventory cost at the point of sale, closes out at period end, and sits between revenue and operating expenses on the income statement.