Register a single-member LLC tomorrow and your federal tax bill will be identical the day after. The IRS puts it plainly: an LLC with one member “is treated as an entity disregarded as separate from its owner, unless it files Form 8832 and affirmatively elects to be treated as a corporation” (IRS).

Same Schedule C. Same self-employment tax. Same number at the bottom.

Tax Disclaimer: This article explains published IRS rules on entity classification and is not tax advice. Entity choice has legal and state-level consequences beyond federal tax; talk to a CPA and, for the liability side, a lawyer.

What the IRS sees when you form one

Nothing, is the short version. The agency’s own language on self-employment tax leaves no room: an individual owner of a single-member LLC running a trade or business “is subject to the tax on net earnings from self employment in the same manner as a sole proprietorship” (IRS).

So 15.3% still applies to 92.35% of net profit, exactly as it did the week before you filed the paperwork. If that mechanism is new to you, the base it is charged on is not your full profit, which is worth understanding before you go looking for ways to shrink it.

An LLC is a state-law liability container. It is not a tax structure. Those are two different products sold in the same sentence.

The thing people are actually thinking of

The tax move is the S corporation election, and it is a separate filing on top of the LLC.

An S corporation splits your profit in two. One part is salary, which carries employment tax. The rest is a distribution, which does not. That gap is the entire saving, and it exists only because the IRS lets some business profit escape the 15.3% charge.

It is also fenced. “S corporations must pay reasonable compensation to a shareholder-employee in return for services that the employee provides to the corporation before non-wage distributions may be made” (IRS). And if you set the salary too low, the agency does not have to accept it: “Distributions and other payments by an S corporation to a corporate officer must be treated as wages to the extent the amounts are reasonable compensation for services rendered” (IRS).

A one-person consultancy where the revenue is unambiguously the owner’s own labour has very little room to argue the salary down. The IRS says as much: what decides the split is whether gross receipts come from the shareholder’s personal services or from capital, equipment and other employees (IRS).

The deduction that takes most of it back

Here is the part the entity-formation pitch leaves out.

The qualified business income deduction is worth up to 20% of your business profit. As a sole proprietor or disregarded LLC, that profit is the whole Schedule C number. As an S corporation, the wages you pay yourself are a business expense, so they come out before the QBI figure is struck.

Which means every dollar you move from distribution to salary saves employment tax and shrinks the QBI deduction at the same time. The two effects run against each other, and on a lot of real businesses they very nearly cancel.

Run it on $120,000 of profit, single filer, below the QBI income thresholds so no wage limitation applies.

As a sole proprietor or single-member LLC

  • SE tax base: $120,000 × 92.35% = $110,820
  • Self-employment tax: about $16,955
  • QBI, after the deductible half of that tax: about $111,522, so a QBI deduction of about $22,304

As an S corporation paying a $70,000 salary

  • Employment tax on the $70,000 salary: about $10,710
  • The $50,000 distribution carries none
  • Employment tax saved: about $6,245
  • But QBI is now the $50,000 pass-through, so the deduction is about $10,000

The QBI deduction fell by roughly $12,300. At a 22% marginal rate that is about $2,707 of extra income tax, against $6,245 of employment tax saved. Net, before any costs: about $3,538.

Then subtract what the structure costs to run. Payroll processing, a separate Form 1120-S, higher preparation fees, and in some states an annual franchise or LLC fee that a sole proprietor never pays. On this profit level the honest answer is that the saving is real but modest, and it is not the multiple-thousand windfall the pitch implies.

Those figures demonstrate the mechanism on round numbers; they are not a computation of your return. The QBI calculator runs the deduction side on your own figures, and two things changed about QBI for 2026 that move the thresholds this arithmetic sits inside.

Where the election starts to make sense

Profit level is the crude test, and it is crude for a reason: the saving scales with the distribution, while the costs are roughly fixed. Below a certain profit the fixed costs eat the whole thing. Well above it they stop mattering.

Two other things push the answer around more than most people expect.

The Social Security ceiling. Employment tax on the larger component stops at $184,500 of combined wage and self-employment income for 2026 (Social Security Administration). Past that, the S corporation is only saving you the Medicare slice, and a large part of the case evaporates.

Where the revenue comes from. A business whose profit is produced by equipment, inventory or employees has a defensible reason to call some of it a return on capital. A solo service business does not.

What the LLC is genuinely for

Liability, mostly, and it is not a small thing. It is the reason to form one, and it stands on its own without any tax story attached.

There are ordinary operational reasons too: a business bank account in the business’s name, contracts signed by an entity rather than a person, and clients whose procurement process will not open a vendor record for an individual. None of those show up on a return, and all of them are real.

Register it because you want the liability shield and the professional footing. Do not register it because someone told you it lowers your taxes, because on its own it does not, and you can check that against the IRS page in a minute.

The bottom line

Three sentences, in order.

An LLC by itself changes your federal tax bill by exactly zero. The S corporation election is the move that changes it, and it is a separate decision with payroll obligations, a reasonable-salary constraint the IRS can police, and a QBI cost that quietly returns a large share of the saving. At solo-service profit levels the net gain is usually a few thousand dollars at most, and it arrives attached to a permanent increase in admin.

So take the two decisions apart. Form the entity for the liability reasons, on their own merits, whenever they apply to you. Then, separately and later, run the election arithmetic on your actual profit with your actual state’s fees in it, and make that call on the number rather than on the pitch. If the profit that would justify it is arriving unevenly, that is its own problem first: an uneven year changes what each quarterly instalment should be, and the 1099 tax estimator will tell you what this year is shaping up to owe before you go restructuring anything.