Gross income for a business is net sales revenue minus the cost of goods sold. It’s the figure that opens every federal business tax return, and everything downstream — deductions, taxable income, the tax you owe — flows from it. For a retailer or manufacturer, the calculation captures what’s left after subtracting the direct cost of the products you sold. For a service business with no inventory, gross income is essentially your total revenue.
The Formula
Net Revenue − Cost of Goods Sold = Gross Income (also called gross profit).
Net revenue is total sales after subtracting returns, allowances for damaged goods, and any early-payment discounts you offered customers. Those adjustments matter because they reflect the actual cash value your sales generated, not the sticker price.
The formula applies most directly to businesses that manufacture, buy, or resell physical products. A retailer buying inventory from a wholesaler, a manufacturer converting raw materials into finished goods, a restaurant purchasing ingredients — each has a meaningful cost of goods sold to subtract. Consulting firms, law practices, and freelance designers typically carry no inventory, so their COGS is zero or negligible and gross income equals net revenue.
How to Calculate Cost of Goods Sold
Cost of goods sold captures only the direct costs tied to the products you actually sold during the year. The IRS formula is beginning inventory, plus purchases or manufacturing costs made during the year, minus ending inventory.1Internal Revenue Service. Publication 334, Tax Guide for Small Business That structure matches costs to the specific inventory that left your shelves, not to everything you bought or produced.
For a retailer, COGS is mainly the purchase price of merchandise. For a manufacturer, it covers three categories:
- Direct materials — raw materials and components that become part of the finished product.
- Direct labor — wages for employees who physically work on converting materials into sellable goods.
- Manufacturing overhead — production-related costs like factory rent, equipment depreciation, utilities powering the production line, and freight on incoming raw materials.1Internal Revenue Service. Publication 334, Tax Guide for Small Business
Costs that keep the business running but aren’t directly tied to production — the CEO’s salary, marketing campaigns, office rent for administrative staff — are operating expenses. They reduce taxable income later in the calculation but never belong in cost of goods sold. This is where the IRS pays close attention, because misclassifying operating expenses as COGS (or vice versa) distorts gross income and can trigger scrutiny.
Inventory Valuation Methods
How you value the inventory you sell changes the final COGS number, sometimes dramatically. The two most common methods are FIFO (first-in, first-out) and LIFO (last-in, first-out).
FIFO assumes the oldest inventory is sold first. When prices are rising, COGS reflects older, cheaper purchase prices, and gross income comes out higher. LIFO flips the assumption: the most recently purchased items are treated as sold first, so COGS reflects newer, higher prices and gross income comes out lower.2Investopedia. Last In, First Out (LIFO) During inflationary periods, LIFO can meaningfully reduce a business’s tax bill by lowering reported gross income.
Whichever method you choose, you generally have to stick with it. Switching requires IRS approval.
Small Business Inventory Exemption
Not every business with inventory needs to go through the full COGS calculation. Under Section 471(c), businesses that meet the gross receipts test in Section 448(c) can skip traditional inventory accounting.3Office of the Law Revision Counsel. 26 USC 471 – General Rule for Inventories For tax years beginning in 2026, the threshold is $32 million in average annual gross receipts over the prior three years.4Internal Revenue Service. Revenue Procedure 2025-32
Qualifying businesses have two simpler options. They can treat inventory as non-incidental materials and supplies, deducting the cost when items are used or sold. Or they can follow whatever method they use on their financial statements or internal books. Tax shelters are excluded from this relief regardless of size.
Other Income That Gets Added In
Gross income for tax purposes isn’t limited to gross profit from your core business. Several other income streams get added to the total.
Interest income. Money earned on business bank accounts, certificates of deposit, or money market funds counts as gross income, even if the amounts are small relative to operating revenue.
Rental income. If you lease out unused warehouse space, extra office rooms, or equipment you’re not currently using, that rental income is part of gross income.
Capital gains. When you sell a business asset — equipment, a vehicle, real estate — for more than its adjusted basis, the difference is a capital gain that gets included in gross income.5Internal Revenue Service. Topic 409, Capital Gains and Losses The adjusted basis is generally what you paid for the asset, reduced by any depreciation you’ve already claimed.
Cancellation of debt income. If a creditor forgives or cancels a business debt, the forgiven amount is generally treated as income under Section 61(a)(12).6Office of the Law Revision Counsel. 26 USC 108 – Income From Discharge of Indebtedness Two exceptions can pull it back out: discharge during a bankruptcy proceeding, and discharge while the business is insolvent (liabilities exceed the fair market value of assets). The insolvency exclusion is capped at the amount by which you’re insolvent immediately before the discharge.
Bad debt recoveries. If you wrote off a customer’s unpaid bill as a bad debt in a previous year and then unexpectedly collected on it, the recovered amount is generally gross income. The tax benefit rule under Section 111 limits this to the extent the original deduction actually reduced your tax.7eCFR. 26 CFR 1.111-1 – Recovery of Certain Items Previously Deducted or Credited
When Revenue Counts as Received
Before you can calculate gross income, you need to know when revenue counts for tax purposes. That depends on your accounting method.
Under the cash method, you recognize revenue when you actually receive payment. A landscaping company that invoices a client in December but gets paid in January reports the income in January’s tax year. The cash method is simpler and gives businesses some control over the timing of income, which is why most sole proprietors and small businesses prefer it.
Under the accrual method, revenue is recognized when it’s earned, regardless of when the check arrives. That December invoice counts as income in December, even if the client pays 60 days later. The accrual method gives a more accurate picture of financial performance in any given period but requires more bookkeeping.
Section 448 generally requires C corporations and partnerships with C corporation partners to use the accrual method.8Office of the Law Revision Counsel. 26 USC 448 – Limitation on Use of Cash Method of Accounting The same $32 million gross receipts test that governs the inventory exemption provides an escape hatch: C corporations and qualifying partnerships below that threshold can still use the cash method.
Constructive Receipt
Cash-method businesses need to watch out for the constructive receipt rule. If income has been credited to your account or made available to you without substantial restrictions, you owe tax on it even if you haven’t physically collected it. A check received on December 30 is taxable that year even if you wait until January to deposit it. A payment a customer has ready for you to pick up is also constructively received once it’s available. The rule prevents businesses from deferring income simply by declining to take possession of money they control. Accrual-method businesses don’t need to worry about constructive receipt because their income recognition already depends on when revenue is earned, not when cash changes hands.
Where Gross Income Appears on Your Tax Return
The specific line depends on your business structure, but the calculation follows the same logic on every form: sales minus returns minus cost of goods sold.
- Sole proprietorships report gross income on line 7 of Schedule C (Form 1040), combining gross profit from sales with any other business income.9Internal Revenue Service. Schedule C (Form 1040) – Profit or Loss From Business
- C corporations calculate gross profit on line 3 of Form 1120 (net sales minus cost of goods sold) and total income on line 11, which adds items like interest and capital gains.10Internal Revenue Service. Form 1120 – U.S. Corporation Income Tax Return
- Partnerships follow the same structure on Form 1065, with gross profit on line 3 and total income on line 8. Each partner receives a Schedule K-1 showing their share.11Internal Revenue Service. Form 1065 – U.S. Return of Partnership Income
- S corporations report gross income similarly on Form 1120-S, and shareholders receive their own K-1s.12Internal Revenue Service. About Form 1120-S, U.S. Income Tax Return for an S Corporation
Regardless of entity type, cost of goods sold is calculated on a separate schedule — Form 1125-A for corporations and partnerships, or lines 35–42 of Schedule C for sole proprietorships — and then subtracted from net sales on the main form.
Gross Income Is Not Taxable Income
Gross income tells you whether the core business model is working. Taxable income tells you what you owe. They’re separated by every allowable deduction a business claims in between.
Those deductions include operating expenses like office rent, utilities, insurance, marketing, and employee wages that aren’t part of COGS. They also include depreciation on business assets, amortization of intangible assets like patents, and deductions for retirement plan contributions or health insurance premiums. For pass-through entities — sole proprietorships, partnerships, and S corporations — the qualified business income deduction under Section 199A may further reduce the taxable figure at the owner level.
A business can have healthy gross income and still report little or no taxable income after deductions. That’s not suspicious; it means the business has significant overhead. A thin gross margin, on the other hand, means the business is spending too much on the goods it sells relative to its prices, and no amount of cost-cutting on overhead can fully fix that.
Penalties for Getting It Wrong
Errors in reporting gross income — whether from understating revenue, overstating cost of goods sold, or omitting non-operating income — can trigger IRS penalties well beyond the extra tax owed.
The accuracy-related penalty under Section 6662 adds 20% on top of any underpayment caused by a substantial understatement of income tax. For most taxpayers, a “substantial” understatement means the tax you reported was off by the greater of 10% of the correct amount or $5,000. Corporations other than S corporations face a different threshold.13Office of the Law Revision Counsel. 26 USC 6662 – Imposition of Accuracy-Related Penalty on Underpayments
Intentional misreporting is far more expensive. The civil fraud penalty under Section 6663 is 75% of the portion of the underpayment attributable to fraud. Once the IRS establishes that any part of the underpayment involved fraud, the entire underpayment is presumed fraudulent, and the burden shifts to you to prove otherwise by a preponderance of the evidence.14Office of the Law Revision Counsel. 26 USC 6663 – Imposition of Fraud Penalty Willful fraud can also lead to criminal prosecution and potential prison time.
The audit triggers most commonly tied to gross income are inconsistencies between reported revenue and third-party information returns like 1099s, unusually high cost of goods sold relative to industry norms, and failing to report non-operating income such as capital gains or debt cancellation. Clean records and honest accounting for every income category above are the most reliable protection.