Handbook / Self-employment tax and 1099s

Schedule C, part by part: how a sole proprietor reports business profit

Schedule C is where a sole proprietor's business turns into a single number on a tax return. It looks intimidating because it lists dozens of expense lines, but it follows a clear order: identify the business, report income, subtract expenses, and arrive at net profit or loss. This guide follows that order. It is based on the IRS Instructions for Schedule C for the 2025 tax year, the version used for returns filed in 2026, which was the current published version when this page was checked. The overall structure tends to stay stable year to year, but always use the instructions for the year you are filing.

First: does your activity count as a business?

The instructions open with a test. An activity qualifies as a business if your primary purpose is income or profit and you are involved with continuity and regularity. They give examples of what does not qualify: a sporadic activity, a not-for-profit activity, or a hobby. Income from a nonbusiness activity is reported elsewhere, on Schedule 1.

In practice, keep evidence that you run the activity as a business: separate records, invoices, marketing, and regular work. That evidence matters if the question ever arises.

The instructions also note Schedule C is used for some special cases, including statutory employees and certain amounts shown on Forms 1099-MISC, 1099-NEC and 1099-K.

The top section: identifying the business

The lines above Part I ask for your principal business or profession, a business code, a business name if you have one, an employer ID number if you have one, the business address, and some yes-or-no questions. Two are worth understanding:

• Line F, accounting method. The instructions say you can generally use the cash method, an accrual method, or another permitted method, as long as it clearly reflects income. Under the cash method you report income when actually or constructively received, which the instructions define as credited to your account or made available to you without restriction, and expenses when paid.
• Line I, Forms 1099. You check "Yes" if you made payments during the year that would require you to file Forms 1099, such as certain payments of fees to contractors.

Line G asks about material participation, which matters mainly if you have a loss. The instructions describe seven tests for it.

Part I: income

Line 1 is gross receipts from your business. The instructions tell you to check any Forms 1099 you received and make sure the amounts properly shown on 1099-NEC forms are included. If box 1 totals from your 1099-NECs exceed what you report on line 1, attach a statement explaining the difference.

This is where good invoicing pays off. Your own record of every payment received should be the main source, with 1099 forms as a cross-check rather than the starting point. A client might send a 1099 that includes a payment you received in a different year, or you might be paid by someone who sends no form at all; the payment is still income.

Part I then subtracts returns and allowances and cost of goods sold (from Part III) to arrive at gross profit, adds other income, and gives gross income.

Part II: expenses

Part II is the long list. It includes lines for advertising, car and truck expenses, contract labor, depreciation, insurance, legal and professional services, office expense, rent, repairs, supplies, taxes and licenses, travel and meals, utilities, wages, and other expenses carried over from Part V.

A few points from the instructions:

• Line 9, car and truck expenses. You can deduct actual expenses or take the standard mileage rate, with conditions. For example, the instructions say you cannot use actual expenses for a leased vehicle if you previously used the standard mileage rate for it.
• Line 30, business use of your home. You use Form 8829 or elect the simplified method, subject to limitations, with details in Publication 587.
• Part V, other expenses. Items that do not fit the named lines are listed here and totalled, then carried to Part II.

If your bookkeeping categories already match these lines, filling in Part II is mostly copying totals.

Part III: cost of goods sold

If you sell products, Part III works out the cost of goods sold from inventory at the beginning and end of the year, purchases, labor, and materials. The instructions include an exception for small business taxpayers on how inventory can be treated. Service businesses with no inventory usually leave this part blank.

Part IV: information on your vehicle

When you claim car or truck expenses, Part IV asks about the vehicle: when it was placed in service, how many miles were business, commuting and other, and whether you have evidence to support the deduction. The form states when this part applies. The instructions define commuting, in most cases, as travel between your home and a work location, and describe trips that count as business travel instead, such as travel to a temporary work location when you have a regular work location away from home. Keep a mileage log during the year so these answers are easy.

Where the profit goes

Line 31 gives net profit or loss. For individuals, the instructions say to include it on Schedule 1 (Form 1040), line 3, and also on Schedule SE (Form 1040), line 2, which figures self-employment tax. Statutory employees and notaries public follow special rules.

What one number does: The net profit on line 31 feeds both your income tax and your self-employment tax, which is why every legitimate expense you record during the year matters twice.

Habits that make Schedule C easy

• Keep business money in a separate account.
• Record each payment received and each expense with a date, amount and category.
• Match your categories to the Schedule C lines.
• Keep a contemporaneous mileage log.
• Save 1099 forms when they arrive and reconcile them against your own income record.

Schedule C rewards the person who did the bookkeeping in January more than the person who starts in April.