Who files Schedule C
Any individual who operates an unincorporated trade or business as a sole proprietor, independent contractor, or single-member LLC (treated as a disregarded entity) generally files Schedule C with their Form 1040. This includes freelancers, gig workers, consultants, and side-hustlers whose activity is regular, continuous, and engaged in for profit. Activities that are sporadic or hobby-like are reported elsewhere on Schedule 1 and are not eligible for business expense deductions.
What it reports
Part I tallies gross receipts or sales, returns and allowances, and cost of goods sold to arrive at gross profit and gross income. Part II lists more than twenty named expense categories — advertising, car and truck expenses, contract labor, depreciation, insurance, legal services, office expense, rent, supplies, taxes and licenses, travel, utilities, wages, and an "Other expenses" worksheet — that reduce gross income to net profit or loss. Parts III through V handle cost of goods sold, vehicle information, and an itemized list of "other" expenses that do not fit a named line.
Key lines to know
Line 1 (Gross receipts) must reconcile to all 1099-NEC, 1099-K, and cash receipts you actually received during the year. Line 9 (Car and truck expenses) ties to either the standard mileage rate or actual expenses computed in Part IV. Line 13 (Depreciation) flows from Form 4562 when you place property in service or claim Section 179 or bonus depreciation. Line 30 (Expenses for business use of your home) flows from Form 8829 unless you elect the simplified safe-harbor method directly on the line.
How net profit flows through
Net profit on Line 31 carries to Schedule 1 of Form 1040 (taxable income) and to Schedule SE (self-employment tax). Because the same dollar of profit is taxed at ordinary income rates and at the 15.3% self-employment rate, every legitimate Schedule C deduction reduces both income tax and SE tax. That double benefit is why disciplined recordkeeping matters more on Schedule C than on most other returns.
Common mistakes
Filers frequently miscategorize personal expenses as business, fail to substantiate vehicle and meal expenses with a contemporaneous log, omit 1099-K income that the platform already reported to the IRS, or forget to file Schedule SE when net profit reaches $400. Another common error is double-deducting health insurance premiums on both Schedule C and the self-employed health insurance adjustment on Schedule 1.