Cost of goods sold is a debit. COGS is an expense account, and in double-entry bookkeeping expense accounts carry a normal debit balance: debits increase the account, credits decrease it. Every time you sell inventory, you debit COGS for the cost of what left the shelf and credit inventory for the same amount. Returns, write-downs, and the year-end closing entry are the situations where COGS gets credited.
Why COGS Sits on the Debit Side
Every account type in double-entry accounting has a “normal” side, meaning the side that increases the balance. Assets and expenses increase with debits. Liabilities, equity, and revenue increase with credits. COGS is an expense, so it follows the expense rule.
The mirroring is deliberate. Revenue accounts grow on the credit side and expense accounts grow on the debit side, so when you net them at the end of a period, the difference is your profit. If COGS grew on the same side as revenue, the math would not work.
The Journal Entry When You Sell Inventory
A sale of inventory usually produces two journal entries, not one. The first records the revenue side: debit cash or accounts receivable, credit sales revenue. The second records the cost side, and this is where COGS shows up:
- Debit: Cost of Goods Sold (for the cost of the item, not its sale price)
- Credit: Inventory (for the same amount)
Two real-world changes are captured at once. You have less inventory on hand, which is why the asset account drops. And you have incurred a cost to earn the revenue you just booked, which is why the expense account rises. The debit and credit are equal, so the books stay balanced.
The amount you record is the cost your business paid or incurred to acquire or produce that item, not what the customer paid you. Direct materials, direct production labor, freight-in, manufacturing overhead, and packaging that is part of the finished product all feed into that cost figure.1Internal Revenue Service. Publication 334, Tax Guide for Small Business Shipping the finished product out to the customer is a selling expense, not part of COGS.
Perpetual vs. Periodic: When the Debit Actually Hits
Whether the COGS debit posts at the moment of sale or at the end of the period depends on which inventory system your books use.
Perpetual System
Under a perpetual system, the COGS entry runs alongside every sale. Sell an item, and the software (or your bookkeeper) immediately debits COGS and credits inventory. The COGS balance is live: you can pull it at any point in the year and see the cost of everything sold to date. Most point-of-sale and inventory platforms operate this way by default.
Periodic System
Under a periodic system, no COGS entry happens at the point of sale. Purchases go into a temporary Purchases account across the year. At period-end, you do a physical count, apply the formula (beginning inventory plus purchases and production costs, minus ending inventory), and record one COGS entry for the whole period. Simpler to maintain, but you are flying without gross-margin visibility until the count is done.
Either way, the direction of the entry is the same: COGS ends up with a debit balance representing the cost of goods sold during the period. The IRS permits businesses to use shrinkage estimates confirmed by a later physical count, provided the business counts regularly at each location and adjusts when the count reveals a difference.2Office of the Law Revision Counsel. 26 U.S. Code 471 – General Rule for Inventories
When COGS Gets Credited
Because the normal balance is a debit, a credit to COGS means something is reducing it. Three situations do that.
Customer Returns
When a customer returns a saleable item, you reverse the cost side of the original entry. Debit inventory to bring the goods back onto the books, and credit COGS for the same cost you originally recorded. The revenue side is reversed separately.
Inventory Adjustments
If a physical count or a corrected cost figure shows that too much cost was pushed into COGS, the correcting entry credits COGS and debits inventory. The reverse happens for shrinkage or write-downs discovered after the fact: debit COGS, credit inventory.
Year-End Closing
At the end of the fiscal year, every expense and revenue account is closed so it starts the new year at zero. For COGS, the closing entry credits the account by whatever its debit balance is and debits an income summary account for the same amount. The income summary then collects all revenues and expenses, and its net balance is transferred to retained earnings. On day one of the new year, COGS is back to zero, and the next sale starts building the debit balance again.
How the Debit Balance Flows to the Income Statement
The debit balance in COGS is not just an internal bookkeeping figure. It is reported directly on the income statement, right below net sales. Sales minus COGS gives you gross profit, and gross profit divided by sales gives you the gross margin percentage. If COGS is understated, gross profit and taxable income are overstated; if it is overstated, the opposite happens. That is why the direction of every entry matters.
Publicly traded companies must separate cost of tangible goods sold from cost of services and from costs tied to other revenue categories on the income statement.3eCFR. 17 CFR 210.5-03 – Statements of Comprehensive Income The mechanics are identical for service businesses that report “cost of services” instead of COGS: the account carries a normal debit balance, increases with debits as services are delivered, and is credited only for adjustments and closing.
One boundary worth flagging. Choosing FIFO, LIFO, or weighted average changes the dollar amount you assign to each sale, but it does not change which side of the account the entry lands on. The debit-and-credit direction described above holds regardless of the valuation method your business uses.