You file Schedule C if you run an unincorporated business by yourself, operate a single-member LLC, receive a W-2 with the statutory employee box checked, or jointly own an unincorporated business with your spouse and elect qualified joint venture treatment. The form reports your business’s profit or loss and attaches to your personal Form 1040, where that bottom-line number drives both your income tax and your self-employment tax.
Sole Proprietors and Single-Member LLCs
The biggest group of Schedule C filers is sole proprietors. If you earn business income on your own and haven’t incorporated, you’re a sole proprietor by default, and your business income and expenses go directly on Schedule C.1Internal Revenue Service. About Schedule C (Form 1040), Profit or Loss from Business (Sole Proprietorship) Freelancers, independent contractors, consultants, gig workers, and people running a side business all fall here.
Single-member LLCs work the same way at the federal level. The IRS treats a one-owner LLC as a “disregarded entity,” meaning you and the business are a single taxpayer for income tax purposes, so the LLC’s activity gets reported on Schedule C just as a sole proprietorship would.2Internal Revenue Service. Single Member Limited Liability Companies Your LLC still provides liability protection under state law; the IRS simply ignores the separate entity for income tax. The exception is if you’ve filed Form 8832 to elect corporate treatment, in which case you file a corporate return instead.
If you run more than one unrelated business as a sole proprietor, you file a separate Schedule C for each.3Internal Revenue Service. Instructions for Schedule C (Form 1040) (2025) A graphic design practice and a rental equipment side business are two Schedules C, not one combined report.
Who Does Not File Schedule C
Three business structures take a different path and should not use Schedule C.
Multi-member LLCs and partnerships file Form 1065, an information return that passes income through to each owner on a Schedule K-1.4Internal Revenue Service. LLC Filing as a Corporation or Partnership C corporations file Form 1120, and S corporations file Form 1120-S.5Internal Revenue Service. About Form 1120, U.S. Corporation Income Tax Return If you’ve chosen any of those structures, Schedule C is the wrong form.
Rental real estate activity and farm income also live elsewhere. Rentals typically go on Schedule E, and farming goes on Schedule F. Schedule C is for a trade or business other than those.
Statutory Employees Who Receive a W-2
A narrow group of workers receives a W-2 and still files Schedule C. These are statutory employees, and the identifying marker is a checked box in Box 13 of the W-2.3Internal Revenue Service. Instructions for Schedule C (Form 1040) (2025) The designation lets them deduct business expenses directly against their earnings on Schedule C.
The IRS recognizes four categories:
- Full-time life insurance agents whose primary work is selling life insurance or annuity contracts for one company.
- Agent or commission drivers who deliver food, beverages, laundry, or dry cleaning on behalf of another business.
- Traveling or city salespersons who work full time soliciting orders from wholesalers, retailers, or similar establishments for a principal.
- Home workers who perform work at home on materials supplied by an employer, following the employer’s specifications.
Statutory employees don’t owe self-employment tax on this income, because Social Security and Medicare taxes were already withheld through their W-2. If you also have ordinary self-employment income on the side, you need two separate Schedules C, one for the statutory employee earnings and one for the self-employment income. You can’t combine them.3Internal Revenue Service. Instructions for Schedule C (Form 1040) (2025)
Spouses Running a Business Together
When spouses co-own and co-run an unincorporated business, the default rule is that they have a partnership and must file Form 1065. The IRS offers an alternative called a qualified joint venture election that lets each spouse file their own Schedule C instead, which skips the partnership return entirely.6Internal Revenue Service. Election for Married Couples Unincorporated Businesses
Three conditions have to be met: you file a joint return, both spouses materially participate in the business, and the business is not held through a state-law entity like an LLC. Each spouse divides the income and expenses by their ownership interest, files a separate Schedule C, and pays self-employment tax on their share.6Internal Revenue Service. Election for Married Couples Unincorporated Businesses Each spouse also builds a separate Social Security earnings record, which can affect retirement benefits later.
Spouses who co-own a business through a multi-member LLC can’t use this election at the federal level, because the LLC is a state-law entity. They file Form 1065 instead.
When Side Income Counts as a Business
Not every money-making activity belongs on Schedule C. The IRS requires that you engage in the work with continuity and regularity, and that your primary purpose is to earn a profit. Sporadic projects or casual activities may not clear that bar. The Supreme Court confirmed this standard in Commissioner v. Groetzinger, drawing a line between business activity and hobbies or amusements.7Justia U.S. Supreme Court Center. Commissioner v. Groetzinger, 480 U.S. 23 (1987)
If the IRS questions whether your venture is a business or a hobby, it looks at factors like whether you keep proper books and records, whether you’ve changed methods to improve profitability, whether you depend on the income for your livelihood, and whether the activity has produced profits in prior years.8Internal Revenue Service. Here’s How to Tell the Difference Between a Hobby and a Business for Tax Purposes No single factor is decisive, but the IRS generally presumes a profit motive if you show a profit in at least three of the last five years.
The stakes matter. If your activity gets reclassified as a hobby, you still owe tax on the income but lose the ability to deduct expenses against it. People often get blindsided here, assuming that because they reported revenue, they can write off their costs. Without a legitimate business purpose, those deductions disappear.
What About 1099-NEC Income?
If you earned $600 or more as an independent contractor from a single client, you’ll receive a Form 1099-NEC reporting that income in Box 1.9Internal Revenue Service. Instructions for Forms 1099-MISC and 1099-NEC That income generally goes on Schedule C. If you earned less than $600 from a client and received no 1099, you still have to report what you earned. The $600 threshold is about the payer’s obligation to issue the form, not about your obligation to report the income.
What Comes With Filing Schedule C
If you’re in the group that files Schedule C, a few consequences follow that W-2 employees don’t deal with.
Net profit from Schedule C triggers self-employment tax, which covers your Social Security and Medicare contributions. The combined rate is 15.3%, split between 12.4% for Social Security and 2.9% for Medicare.10Internal Revenue Service. Self-Employment Tax (Social Security and Medicare Taxes) You pay both the employee and employer halves, which is why the rate is roughly double what a regular employee sees withheld. The taxable base is 92.35% of your net profit rather than 100%, and you can deduct half of the self-employment tax you pay as an adjustment to income on Schedule 1.11Internal Revenue Service. Topic No. 554, Self-Employment Tax
The 12.4% Social Security portion only applies to net earnings up to $184,500 for 2026.12Social Security Administration. 2026 Cost-of-Living Adjustment (COLA) Fact Sheet Income above that is still subject to the 2.9% Medicare portion, which has no cap. An additional 0.9% Medicare surtax applies to the excess once combined self-employment and wage income passes $200,000 for single filers or $250,000 for married couples filing jointly.13Internal Revenue Service. Instructions for Form 8959 (2025)
Because no employer is withholding taxes from your Schedule C income, you’re generally responsible for making quarterly estimated tax payments. The IRS expects these if you’ll owe $1,000 or more after subtracting withholding and refundable credits.14Internal Revenue Service. 2026 Form 1040-ES Estimated Tax for Individuals For the 2026 tax year, the quarterly deadlines are April 15, 2026, June 15, 2026, September 15, 2026, and January 15, 2027.15Taxpayer Advocate Service. Making Estimated Payments Missing them results in an underpayment penalty that works like interest, and many first-year filers don’t realize these payments exist until they file their return and owe a lump sum plus a penalty.
Schedule C itself is filed with your Form 1040 on the standard April 15 deadline. An extension on Form 4868 pushes the filing date to October 15 but does not extend the time to pay; any tax owed is still due April 15.16Internal Revenue Service. Get an Extension to File Your Tax Return The failure-to-file penalty is 5% of unpaid tax per month, capped at 25%.17Internal Revenue Service. Failure to File Penalty
If Schedule C shows a loss rather than a profit, the loss offsets other income on your return, including wages and a spouse’s earnings on a joint return, subject to the excess business loss rules that convert anything over the annual threshold into a net operating loss carried forward.3Internal Revenue Service. Instructions for Schedule C (Form 1040) (2025) Reporting losses year after year is also one of the factors the IRS weighs in the hobby question, so keep records showing the steps you’ve taken to reach profitability if your early years are in the red.