Profit or Loss from Business (Sole Proprietorship)

Who Files Schedule C

Self-employed individuals operating as sole proprietors or single-member LLCs that did not elect corporate tax treatment. Includes freelancers, gig workers (rideshare, delivery, instacart), independent consultants, online sellers (Etsy, eBay, Shopify), small service businesses, and side-hustle earners. Each separate business activity gets its own Schedule C; a person with two unrelated businesses files two Schedule Cs.

What Schedule C Reports

Part I reports gross receipts, returns and allowances, cost of goods sold (Part III), and gross profit. Part II reports operating expenses across 25+ standard categories: advertising, vehicle (with mileage method on Part IV or actual expenses), commissions and fees, contract labor, depreciation, insurance, interest, legal and professional fees, office expense, rent, repairs, supplies, taxes and licenses, travel, meals (50 percent deductible), utilities, wages, and home office (carried from Form 8829 unless using simplified method). Net profit or loss flows to Form 1040 as ordinary income and to Schedule SE for self-employment tax.

Key Deadlines

• April 15: filed with Form 1040
• October 15: extended deadline with Form 4868
• Quarterly estimated tax via Form 1040-ES on April 15, June 15, September 15, January 15

Common Mistakes

• Mixing personal and business expenses in the same bank account or credit card. The IRS requires clear separation; commingling triggers audit risk and disallowed deductions.
• Claiming 100 percent vehicle business use without contemporaneous mileage logs. Standard mileage method requires date, destination, business purpose, and miles for each trip.
• Failing the home office regular and exclusive use test. Using the space for any personal purpose (kids homework, guest room) disqualifies it.
• Missing the Section 199A QBI deduction. Most non-SSTB Schedule C income qualifies for the 20 percent deduction.
• Skipping estimated tax payments. Self-employment tax (15.3 percent) plus federal income tax with no withholding triggers underpayment penalties under Section 6654.

Best Practices

• Open a dedicated business bank account and credit card from day one. Even single-member LLCs benefit from clean separation, and it makes Schedule C preparation 10x faster.
• Use accounting software (QuickBooks Online, Xero, Wave) connected to your business accounts. Categorizing transactions monthly is far easier than reconstructing a year of activity at tax time.
• Track vehicle mileage with an app (MileIQ, Stride, TripLog) that auto-records trips. Standard mileage rate is 70 cents per mile in 2025, often higher than actual expense method for ordinary cars.
• Pay quarterly estimated taxes on time (April 15, June 15, September 15, January 15). Use the prior-year safe harbor if calculation is uncertain.
• Once net profit reliably exceeds $50K to $80K, evaluate S-Corp election (Form 2553). The self-employment tax savings often exceed the cost of running payroll.
• Document business purpose for meals and travel with notes on the receipt or in your accounting software. Vague entries get disallowed in audit.

Source: Official Schedule C information at IRS.gov