How to Fill Out 1040 Schedule C: Income, Expenses, and Net Profit

To fill out Schedule C, work through the form top to bottom: complete the identifying header (Lines A through J), report your income in Part I, calculate cost of goods sold in Part III if you sell products, list your deductible expenses in Part II with Part IV backing up any vehicle costs and Part V holding any miscellaneous items, then land on Line 31 for your net profit or loss. That bottom-line number moves to Schedule 1 of your Form 1040 and, if it’s $400 or more, to Schedule SE for self-employment tax. Here’s how each part works.

Gather Your Records First

Before you open the form, pull together every 1099-NEC and 1099-K you received, bank and payment-processor statements covering any income not reported on a 1099, and receipts or logs for the expenses you plan to deduct. If you sell physical products, you also need your beginning-of-year and end-of-year inventory values. The IRS matches 1099s against your return, so income you forget to include is the fastest route to a notice.

The Header: Lines A Through J

The top of Schedule C identifies you and the business.

Line A asks for a plain-English description of what your business does. Line B is the six-digit Principal Business or Professional Activity Code, which you look up in the Schedule C instructions. Line D is your Employer Identification Number; many sole proprietors leave it blank and use their Social Security Number, but you need an EIN if you have employees or maintain certain retirement plans.¹ Line E is the business address, which can be your home if you don’t have a separate office.

Line F asks you to pick an accounting method. Cash means you record income when received and expenses when paid, and it’s what most sole proprietors use. Accrual records transactions when they happen regardless of payment timing. Unless inventory rules force you into accrual, cash is simpler.²

Line G asks whether you materially participated in the business. For someone actively running their own operation, the answer is yes; if you didn’t, the IRS treats the activity as passive and your losses may be limited. Lines H through J cover whether the business started this year, whether you made payments requiring 1099s, and whether you filed them.²

Part I: Income

Line 1 is your total gross receipts: every dollar customers or clients paid you during the year, whether or not it appeared on a 1099. Line 2 is returns and allowances, which is where refunds and post-sale price reductions go.²

If you sell products, Line 4 pulls in your cost of goods sold from Part III. If you provide services, you skip Part III and leave Line 4 blank. Either way, Line 7 gives you gross income.

Part III: Cost of Goods Sold

Product sellers detour to Part III near the bottom of the form. Enter your beginning-of-year inventory, purchases during the year, cost of labor directly tied to production, materials and supplies, and any other production costs. Add these to beginning inventory, subtract ending inventory, and the result is cost of goods sold. That total goes on Line 42 and flows back to Line 4 in Part I.³

Part II: Expenses

Federal law lets you deduct expenses that are ordinary (common in your field) and necessary (helpful and appropriate for the business).⁴ Part II breaks these into named lines. Enter the total you actually spent in each category during the year.

Line 8, advertising: website costs, online ads, business cards, promotional materials.
Line 9, car and truck expenses: total from Part IV.
Line 11, contract labor: payments to independent contractors. Do not put employee wages here.³
Line 13, depreciation and Section 179: total from Form 4562.
Line 15, insurance: business liability, professional indemnity, and similar coverage. Health insurance for yourself is not entered here.³
Line 17, legal and professional services: accountant and attorney fees tied to the business.
Line 18, office expenses: supplies, postage, and similar costs.
Line 20a, rent or lease of vehicles, machinery, and equipment.⁵
Line 24b, deductible meals: enter 50% of the actual cost, not the full amount. If you spend $80 on a business lunch, $40 goes on Line 24b.⁶
Line 26, wages: salaries to your employees, reduced by any employment credits.⁵

Legitimate expenses that don’t match any named line go on Line 27a, with the itemized breakdown in Part V. Common Part V entries include bank fees, software subscriptions, professional memberships, and continuing education.³

Add Lines 8 through 27a to get total expenses on Line 28.

Part IV: Vehicle Expenses

Anything you put on Line 9 has to be substantiated in Part IV. Enter the date the vehicle was first used for business and the year’s total miles broken into business, commuting, and personal categories, and answer the questions about availability for personal use. Federal law requires you to document the amount, time, place, and business purpose of each trip, so keep a mileage log or a spreadsheet updated after each trip.⁷

You pick one of two calculation methods. The standard mileage rate for 2026 is 72.5 cents per business mile and bundles fuel, maintenance, insurance, and depreciation into one figure.⁸ If you own the vehicle, you must elect the standard rate in the first year you use it for business. The alternative is actual expenses: gas, oil changes, tires, insurance, registration, and depreciation, multiplied by your business-use percentage. Actual expenses make sense when vehicle costs are high relative to miles driven, but they require far more documentation.

Line 30: Home Office

If part of your home is used exclusively and regularly for business, Line 30 is where the home office deduction lands. “Exclusively” is strict: the space can’t double as a guest room or play area, even occasionally. The home also has to be your principal place of business, meaning you handle your administrative and management work there and have no other fixed location for those tasks.⁹

You choose between two methods. The simplified method gives you $5 per square foot of dedicated business space, capped at 300 square feet, so the largest possible deduction is $1,500.¹⁰ The regular method requires actual home expenses (mortgage interest or rent, utilities, insurance, repairs) multiplied by the business-use percentage. It’s more paperwork but often produces a larger deduction when the office takes up a meaningful share of the home.

Line 13: Depreciation and Section 179

Equipment, furniture, and other business assets expected to last more than a year generally can’t be deducted in full the year you buy them. You depreciate them over their useful life on Form 4562 and carry the total to Line 13.

Section 179 is the shortcut. It lets you expense the full cost of qualifying equipment in the year you buy and place it in service. For 2026, the cap is $2,560,000, phasing out once total qualifying purchases exceed $4,090,000. Computers, office furniture, machinery, and certain vehicles all qualify.

Line 31: Net Profit or Loss

Subtract Line 30 from Line 29 (gross income minus expenses, adjusted for any home office deduction) to reach Line 31. A positive number is your net profit; a negative number is a net loss.

Line 31 flows to Line 3 of Schedule 1 (Form 1040), where it feeds into your adjusted gross income.¹¹ A net loss can offset W-2 wages, investment income, or a spouse’s earnings on a joint return. If you show a loss, you also check the boxes on Line 32 indicating whether all your investment in the activity is at risk.

A Note on Repeated Losses

If your Schedule C shows a loss year after year, the IRS may reclassify the activity as a hobby. The general presumption is that an activity is a business if it produced a profit in at least three of the last five tax years. Failing the test doesn’t automatically doom you, but it shifts the burden to you to prove you’re genuinely trying to make money.¹² Hobby expenses aren’t deductible, so losing business status means paying tax on the gross income with nothing to offset it.

Forms That Come After Schedule C

Schedule C rarely stands alone. If Line 31 is $400 or more, you owe self-employment tax and file Schedule SE. The rate is 15.3% (12.4% Social Security plus 2.9% Medicare), applied to 92.35% of your net earnings. Social Security stops at $184,500 in combined wages and self-employment income for 2026; Medicare has no cap, and an extra 0.9% surtax applies once self-employment income tops $200,000 ($250,000 married filing jointly).¹³ You deduct half of the self-employment tax as an adjustment to income on Schedule 1.¹⁴

The Qualified Business Income deduction is the one sole proprietors most often miss. Section 199A allows eligible owners to deduct up to 20% of qualified business income on Form 8995 (or 8995-A for higher-income filers). It comes off after adjusted gross income, so it reduces income tax but not self-employment tax.¹⁵ Originally set to expire after 2025, it was made permanent by the One Big Beautiful Bill Act. For 2026, taxable income below roughly $200,000 (single) or $400,000 (married filing jointly) generally gets the full 20% with no extra limits. Above those thresholds the math gets more complex, and for specified service businesses (law, accounting, health care, consulting) the deduction phases out entirely once income exceeds roughly $275,000 (single) or $550,000 (joint).

If you pay your own health, dental, vision, or qualifying long-term care premiums and Schedule C shows a profit, you can deduct those premiums on Form 7206 and claim the total as an adjustment to income on Schedule 1, not as a Schedule C expense.¹⁶ You can’t take the deduction for any month you were eligible to join an employer-subsidized plan through yourself, a spouse, or a parent, and the deduction can’t exceed your net self-employment income.

Filing, Deadlines, and Quarterly Payments

Schedule C attaches to your Form 1040 (or 1040-SR). Tax software handles the attachment automatically and typically generates Schedule SE, Form 8995, and any other required forms from your entries. E-filing is faster, produces fewer errors, and gives you an electronic acceptance confirmation. If you file on paper, mail the complete package to the IRS service center for your state; certified mail gives you proof of the postmark. The standard deadline is April 15. Form 4868 extends the filing deadline to October 15 but does not extend the payment deadline; interest and penalties on unpaid balances start April 16.

Sole proprietors also pay taxes as they earn. If you expect to owe at least $1,000 after withholding and refundable credits, you’re required to make quarterly estimated payments using Form 1040-ES. For 2026, the deadlines are April 15, June 15, September 15, and January 15, 2027.¹⁷ To avoid an underpayment penalty, your payments must cover at least the smaller of 90% of the current year’s tax or 100% of last year’s (110% if your prior-year adjusted gross income exceeded $150,000, or $75,000 if married filing separately).¹⁸ Skipping the quarterlies means owing a full year of income tax and self-employment tax in one lump in April.

Keep the records behind every line. Federal law requires documentation supporting every item of income, deduction, and credit on the return, generally for three years from the filing date.¹⁹²⁰ For depreciated property, hold purchase records at least three years after you dispose of the asset so you can calculate gain or loss on the sale.

1
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Internal Revenue Service. IRS Sets 2026 Business Standard Mileage Rate at 72.5 Cents Per Mile, Up 2.5 Cents
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