Schedule C for single-member LLCs

A single-member LLC is a "disregarded entity" for federal tax purposes by default. The IRS treats it as a sole proprietorship. All business income and expenses flow through to the owner's Form 1040 on Schedule C.

What goes on Schedule C

Schedule C has 47 lines. The ones that matter most:

• Line 1 · Gross receipts. Total revenue collected, before deductions or refunds.
• Line 2 · Returns and allowances. Refunded sales, returned merchandise.
• Lines 8-27 · Deductible expenses. Advertising, supplies, software subscriptions, mileage, professional fees, contractor payments (1099-NEC), insurance, rent, utilities.
• Line 30 · Home office deduction. Simplified method ($5/sqft up to 300 sqft = $1,500 max) or actual expenses with Form 8829.
• Line 31 · Net profit (or loss). Gross income minus all expenses. This number flows to Schedule 1 of your 1040.

Self-employment tax

The Schedule C net profit also drives Schedule SE · self-employment tax of 15.3% on the first $168,600 of net earnings (2024 wage base, indexed annually). This is the part of LLC tax that surprises new founders. The "I just made $50K profit" reality is "$50K × 92.35% × 15.3% = $7,065 in SE tax" before any income tax even applies.

This is the cost that the S-Corp election eventually saves once net profit clears about $40K. See our LLC vs S-Corp guide for the breakeven math.

Common mistakes

• Failing to make quarterly estimated tax payments. Underpayment penalty kicks in if you owe more than $1,000 at filing.
• Mixing personal and business expenses. The home office deduction requires "regular and exclusive use" of the space.
• Treating health insurance as a Schedule C deduction instead of a 1040 Schedule 1 deduction (where it belongs for self-employed individuals).
• Not tracking mileage. The 2024 standard rate is $0.67/mile. Without a contemporaneous log, the deduction is at risk if audited.

Need help filing?

Our accountant directory has specialists who handle this exact form across foreign-owned LLCs, S-Corps, and high-volume single-member LLCs.