If you are self-employed — as a sole proprietor, single-member LLC, freelancer, or independent contractor — you file Schedule C (Profit or Loss from Business) as part of your annual Form 1040. Schedule C determines your net profit (or loss), which flows to Form 1040 as taxable income and to Schedule SE for self-employment tax calculation. Getting Schedule C right is essential: it is one of the IRS's most-scrutinised forms, and errors can trigger notices, audits, or missed deductions that cost you money. This complete guide walks you through every step.
You must file Schedule C if you earned income as a sole proprietor, operated a business as a single-member LLC (not taxed as S-corp or C-corp), or received income reported on Form 1099-NEC, 1099-K, or other self-employment income forms — and you are in business for profit (not a hobby). If you have multiple unrelated businesses, you file a separate Schedule C for each. Partnerships file Form 1065; S-corporations file Form 1120-S; C-corporations file Form 1120.
Report your gross receipts or sales on Line 1. This includes all income from your business — cash, checks, electronic payments, 1099-NEC income, 1099-K income, barter income, and any other compensation for services or goods. Common mistake: under-reporting income because you did not receive a 1099 form. All income is taxable regardless of whether a 1099 was issued.
Schedule C Part II provides pre-labelled lines for common business expense categories. Each expense must be ordinary (common in your industry) and necessary (helpful and appropriate for your business). Document every deduction with receipts, bank statements, or records.
| Schedule C Expense Line | What It Covers | Key Documentation |
|---|---|---|
| Line 8: Advertising | Online ads, print, signage, promotions | Invoices, platform billing records |
| Line 9: Car and truck expenses | Actual expenses or standard mileage rate | Mileage log with business purpose |
| Line 13: Depreciation (Form 4562) | Equipment, computers, Section 179, bonus | Purchase receipts; Form 4562 |
| Line 18: Office expense | Supplies, postage, small equipment | Receipts and purchase records |
| Line 19: Pension/profit-sharing | SEP-IRA, Solo 401(k) employer contributions | Contribution records, plan documents |
| Line 24: Travel/meals | Business travel (100%); business meals (50%) | Receipts + business purpose + attendees |
| Line 25: Utilities | Business-use portion of phone, internet, utilities | Bills; business-use percentage calculation |
| Line 30: Home office | Regular and exclusive business-use portion of home | Floor plan, measurements; Form 8829 |
Once Schedule C net profit is calculated, it flows to Schedule SE. The SE tax is calculated on 92.35% of net self-employment income (this adjustment accounts for the fact that employees pay SE tax only on wages, not on the employer's share). The SE tax rate is 15.3% on SE income up to the Social Security wage base, plus 2.9% Medicare on income above that. You then deduct 50% of the SE tax as an above-the-line deduction on Schedule 1 — reducing your AGI.
Self-employed individuals operating a qualifying business may deduct up to 20% of their qualified business income (QBI) under Section 199A, subject to income limits and restrictions for specified service trades or businesses (SSTBs). For income below the threshold ($197,300 single / $394,600 MFJ for 2026), the deduction is generally straightforward: 20% of net self-employment income. For higher incomes, W-2 wage and qualified property limitations apply — making entity structure planning (e.g., S-corp election) potentially valuable.