LLC vs Sole Proprietorship Taxes: Why the LLC Alone Changes Nothing

Sole proprietorships and LLCs are both pass-through entities. Neither pays its own federal income tax — profit flows straight to the owner's personal Form 1040 and gets taxed at the owner's rates. That's the whole reason an LLC, by default, doesn't save tax: there's no second layer to eliminate.

• Sole proprietor.No entity at all in the IRS's eyes. You report business income on Schedule C and attach it to your 1040. You pay SE tax on Schedule SE.
• Single-member LLC.A "disregarded entity" by default — the LLC exists for state law and liability, but federal tax treats it as if the LLC didn't exist. Same Schedule C, same Schedule SE, same outcome.
• Multi-member LLC. Default tax treatment is a partnership — files Form 1065, and each member gets a K-1. Active partners pay SE tax on their share of operating income.
• LLC electing S-corp. The LLC keeps its state-law identity but files Form 1120-S federally. The owner-employee draws a W-2 salary; remaining profit flows through as a distribution that escapes SE tax. This is the only path among these four where SE tax actually shrinks.

Whether you operate as a sole proprietor or a single-member LLC, every dollar of net profit hits the full 15.3% self-employment tax — 12.4% Social Security up to the wage base ($168,600 in 2024) plus 2.9% Medicare with no cap. There is no SE tax discount for being an LLC. The IRS computes SE tax on net Schedule C profit, not on the legal wrapper around it.

Half of SE tax is deductible as an above-the-line adjustment on Form 1040 — that's the same for both structures too. For a full breakdown of how SE tax stacks with income tax, see SE tax vs. income tax.

An LLC (or a corporation) can file Form 2553 to be taxed as an S-corp. After the election, the owner is both a shareholder and an employee:

• Reasonable salary. The owner pays themselves a W-2 wage that the IRS considers reasonable for the work performed — typically benchmarked against what a third party would charge. FICA (the W-2 equivalent of SE tax) applies to this salary, with the company paying 7.65% and the employee paying 7.65%.
• Distribution. Profit above the salary flows through to the owner as a distribution. Distributions are taxed as ordinary income but not subject to SE tax or FICA. This is the tax savings.
• Setting the split. A common rule of thumb is a 60/40 or 50/50 split between salary and distribution at moderate incomes. Set salary too low and the IRS can reclassify distributions as wages, with back taxes and penalties. Set it too high and the savings disappear.

The S-corp election adds real overhead: payroll service, quarterly Form 941 filings, year-end W-2 and W-3, a separate Form 1120-S return, and usually a CPA. Expect $1,500-$3,000 a year in compliance costs. That overhead is the reason the election isn't free money below a certain income.

Both sole proprietors and default-taxed LLCs send quarterly 1040-ES payments covering federal income tax and SE tax — there's no withholding source. After an S-corp election, the salary portion gets W-2 withholding from the company, and 1040-ES only needs to cover the tax on the distribution and any other non-withheld income.

The IRS safe harbor (pay 100% of last year's tax, or 110% if AGI > $150K) applies identically to all three structures. Use the quarterly tax calculator to size each voucher.

Federal tax is only half the picture. Your state likely charges an LLC fee or annual report that a sole proprietor avoids entirely:

• California:$800 minimum franchise tax for any LLC, plus a gross-receipts fee starting at $250K of California-source income. The franchise tax alone can wipe out the LLC's value for a side hustle under $20K of profit.
• Delaware:$300 annual franchise tax, no state income tax on LLCs that don't operate in Delaware.
• Texas, Wyoming, Nevada: Low or no state income tax, modest LLC reports — popular formation states.
• Most other states: $50-$200 annual report fee, no franchise tax.

Sole proprietors generally owe nothing at the entity level — they file the same state personal return they would otherwise. If your only motivation for the LLC is tax savings, check your state's LLC cost first.

The LLC's real value isn't tax — it's liability separation. A sole proprietor and the business are legally one entity: a customer suit, a contractor injury, or a vendor dispute can reach your personal bank account, your car, your house. An LLC stands between those exposures and your personal assets, provided you respect the corporate form (separate bank account, clean records, no commingling).

The LLC also makes you look more professional, lets you sign contracts in the company's name, and creates an entity that can later elect S-corp status without a fresh formation. For most service businesses, that combination is worth the modest annual cost — just not because of the federal tax math.