To file taxes for a single-member LLC on Schedule C, you report the business’s income and expenses on Schedule C (Form 1040), calculate self-employment tax on Schedule SE, and submit both with your personal Form 1040. The LLC itself does not file a separate federal income tax return. You are also responsible for paying income tax and self-employment tax throughout the year through quarterly estimated payments.
Why Schedule C Is the Right Form
Federal regulations treat a single-member LLC as a “disregarded entity” for income tax purposes unless the owner elects otherwise.1eCFR. 26 CFR 301.7701-3 – Classifications of Certain Business Entities The LLC still shields your personal assets under state law, but the IRS looks through it and taxes you as if you were a sole proprietor. Every dollar of revenue and every deductible expense lands on your personal Form 1040.
You can use your Social Security number on Schedule C if the LLC has no employees and no excise tax obligations, though most owners obtain an EIN anyway.2Internal Revenue Service. Single Member Limited Liability Companies If your LLC has elected to be taxed as a corporation or S corporation, Schedule C does not apply and you file a separate business return instead.
Gather Your Records First
Before opening the form, pull together everything Schedule C will ask about.
On the income side, collect any Form 1099-NEC from clients who paid you $600 or more and any Form 1099-K from payment platforms or card processors.3Internal Revenue Service. About Form 1099-NEC, Nonemployee Compensation You owe tax on all business income regardless of whether a 1099 was issued, so bank deposits and invoices matter as much as the forms clients send.
On the expense side, organize receipts by category: advertising, supplies, insurance, professional fees, and the rest of your operating costs. Two categories have their own rules worth knowing before you start filling in numbers.
Home Office
If a portion of your home is used regularly and exclusively for business, you can deduct it. The simplified method allows $5 per square foot, up to 300 square feet, capping the deduction at $1,500.4Internal Revenue Service. Simplified Option for Home Office Deduction The regular method tracks actual costs (mortgage interest, utilities, repairs) and allocates them by the business-use percentage of your home. The regular method takes more recordkeeping and often produces a larger number.
Vehicle Use
For business driving, you choose between the standard mileage rate and actual expenses. The 2026 standard mileage rate is 72.5 cents per mile.5Internal Revenue Service. IRS Sets 2026 Business Standard Mileage Rate at 72.5 Cents Per Mile, Up 2.5 Cents Claiming it requires a contemporaneous mileage log with date, destination, business purpose, and miles. Commuting between home and a regular workplace doesn’t count.
Filling Out Schedule C
Schedule C reports gross income, subtracts business expenses, and produces net profit or loss.6Internal Revenue Service. About Schedule C (Form 1040), Profit or Loss from Business (Sole Proprietorship) The top of the form asks for:
- Your business name and address
- Your EIN or Social Security number
- A principal business activity code, drawn from the NAICS list in the Schedule C instructions
- Your accounting method (cash or accrual)
Part I reports gross receipts and returns. Part II lists deductible expenses by category. Part III applies only if you sell physical products; it calculates cost of goods sold using beginning and ending inventory values, which then flow into gross profit. Service businesses without inventory skip this section. Parts IV and V cover vehicle information and any expense category not listed elsewhere on the form.
The net profit or loss at the bottom of Schedule C moves to your Form 1040 as ordinary income. A net loss can offset other income on your return, within some limits. That same net profit figure feeds directly into Schedule SE.
Self-Employment Tax on Schedule SE
Schedule SE is where the self-employment tax gets calculated. Because you’re both employer and employee, you pay both sides of Social Security and Medicare: 12.4% for Social Security and 2.9% for Medicare, a combined 15.3%.7Office of the Law Revision Counsel. 26 USC 1401 – Rate of Tax The tax kicks in once your net self-employment earnings hit $400 for the year.
Two limits shape the math. For 2026, the Social Security portion applies only to the first $184,500 of combined wages and self-employment income.8Social Security Administration. What Is the Current Maximum Amount of Taxable Earnings for Social Security The Medicare portion has no cap. Single filers with self-employment income above $200,000 owe an additional 0.9% Medicare tax on the amount over that threshold.9Internal Revenue Service. Questions and Answers for the Additional Medicare Tax
One relief built into the system: you can deduct half of your self-employment tax when calculating adjusted gross income.10Internal Revenue Service. Topic No. 554, Self-Employment Tax This adjustment is available whether or not you itemize.
The Qualified Business Income Deduction
Section 199A allows eligible single-member LLC owners to deduct up to 20% of qualified business income before calculating income tax.11Internal Revenue Service. Qualified Business Income Deduction The One Big Beautiful Bill Act made the deduction permanent, so it continues to apply for 2026.
If your taxable income sits below the 2026 phase-out range (roughly $201,750 to $276,750 for single filers), you take the full 20%. Within the range the deduction phases down, and the rules differ for “specified service trades or businesses” such as law, medicine, accounting, and consulting. Above the range, service businesses lose the deduction entirely, and other businesses face limits tied to W-2 wages and property owned.
For 2026, a minimum QBI deduction of $400 is available to taxpayers with at least $1,000 of qualified business income from an actively conducted business. The deduction is claimed on Form 1040 and reduces taxable income only; it does not reduce the earnings subject to self-employment tax.
Quarterly Estimated Tax Payments
No one withholds tax from your LLC profits, so the IRS expects you to pay as you go using Form 1040-ES.12Internal Revenue Service. About Form 1040-ES, Estimated Tax for Individuals These payments cover both income tax and self-employment tax, and you generally owe them if you expect to owe at least $1,000 for the year.
For tax year 2026, the payment deadlines are:
- First quarter: April 15, 2026
- Second quarter: June 15, 2026
- Third quarter: September 15, 2026
- Fourth quarter: January 15, 2027
IRS Direct Pay transfers funds from your bank account at no charge.13Internal Revenue Service. Payments The IRS has stopped accepting new individual enrollments for EFTPS, but existing users can continue with it.14Internal Revenue Service. EFTPS: The Electronic Federal Tax Payment System You can also pay through your IRS Online Account.
Safe Harbor
Estimating precisely is hard when income fluctuates. Safe harbor rules shield you from underpayment penalties if you pay at least 90% of the current year’s tax or 100% of the prior year’s tax, whichever is less.15Internal Revenue Service. Underpayment of Estimated Tax by Individuals Penalty If your prior-year adjusted gross income exceeded $150,000, the 100% figure rises to 110%. Paying 100% (or 110%) of last year’s total tax in equal installments is the simplest way to stay safe.
Filing the Return
Once Schedule C, Schedule SE, and any other applicable forms are complete, attach them to your Form 1040 and submit the package as one return.
IRS Free File offers free guided software to taxpayers with adjusted gross income of $89,000 or less.16Internal Revenue Service. 2026 Tax Filing Season Opens With Several Free Filing Options Available Above that income level, commercial tax software will e-file the return for a fee. Electronic returns usually receive acceptance confirmation within 24 to 48 hours.17Internal Revenue Service. Processing Status for Tax Forms
Paper filing is still available. The mailing address depends on your state and whether you’re enclosing a payment; the Form 1040 instructions list both. Paper processing typically runs six to eight weeks, versus around three weeks for e-filed returns. The “Where’s My Refund?” tool on the IRS website tracks either type.
Penalties for Missing a Deadline
Late filing costs more than late paying, and the two penalties stack.
The failure-to-file penalty is 5% of the unpaid tax for each month or partial month the return is late, up to 25%.18Internal Revenue Service. Topic No. 653, IRS Notices and Bills, Penalties and Interest Charges After 60 days late, a minimum penalty of $525 or 100% of the tax owed (whichever is smaller) applies. Filing on time even without full payment avoids this larger charge.
The failure-to-pay penalty is 0.5% of the unpaid balance per month, also capped at 25%.19Internal Revenue Service. Failure to Pay Penalty An approved IRS payment plan drops the rate to 0.25% per month. When both penalties apply in the same month, the failure-to-file penalty is reduced by the failure-to-pay amount.
Interest accrues on any unpaid balance from the original due date until the balance is paid, compounded daily. The current rate for individual underpayments is 7% per year, based on the federal short-term rate plus three percentage points.20Internal Revenue Service. Interest Rates Remain the Same for the First Quarter of 2026 Interest continues to run even while you’re on a payment plan.