Most small business owners pick an entity type based on what a friend did or what a cheap online filing service suggested. That decision can lock in thousands of dollars in extra tax every single year, especially under the post 2018 tax rules.

If you are trying to understand 2018 taxes LLC vs sub s vs c corp treatment and what still matters today, you are asking the right question. The Tax Cuts and Jobs Act reshaped how business income is taxed, and those rules continue to drive planning for 2024 and 2025 for California owners.

Quick Answer: How These Three Entity Types Really Get Taxed

Here is the short version in plain English:

• Default LLC (taxed as sole proprietor or partnership) income flows straight to your personal return and is usually hit with income tax plus self employment tax up to 15.3 percent.
• S corporation income passes through to you, but only the W 2 salary portion is subject to payroll tax. The remaining profit avoids self employment tax if the salary is reasonable.
• C corporation income is taxed at a flat corporate rate, then taxed again when paid to you as dividends. In exchange you get more flexibility keeping profits inside the company.

For many profitable service businesses between about 80,000 and 600,000 of net income, S status can reduce total tax materially. But that is not universal, and choosing just by rules of thumb is risky.

How 2018 Tax Law Changed The Game

The 2018 law introduced the qualified business income deduction in Internal Revenue Code Section 199A. For pass through entities like LLCs and S corporations, many owners can deduct up to 20 percent of qualified profit on their individual returns, subject to limits. You will find the core rules in IRS Publication 535 and the Section 199A regulations.

In practice, that means a consultant with 200,000 of LLC profit might only pay income tax on 160,000 before other deductions, if fully eligible for the 20 percent deduction. An S corporation owner might achieve a similar result as long as the structure and salary are set correctly. C corporation owners do not get this deduction at the corporate level, so the math is different.

If you own or are planning an LLC, there is a broader blueprint of strategies in our LLC tax planning guide for California owners, which shows how pass through rules interact with California franchise tax.

Baseline: How A Single Member LLC Is Taxed

Start from the simplest structure, then build up. A single member LLC with no special elections is a disregarded entity for federal purposes. The IRS sees you as a sole proprietor filing Schedule C or Schedule E with your Form 1040.

Income And Self Employment Tax

Every dollar of net profit from your Schedule C is subject to income tax plus self employment tax, which covers Social Security and Medicare. For 2026, the combined self employment rate is typically 15.3 percent on the first Social Security wage base and 2.9 percent Medicare beyond that, plus potential 0.9 percent additional Medicare for higher earners. The mechanics are in IRS Schedule SE instructions.

Example: Maria, a California marketing consultant, has 150,000 net Schedule C profit from her single member LLC.

• Income tax: Assume a blended 24 percent federal plus 9.3 percent California marginal rate on much of that income.
• Self employment tax: Roughly 15.3 percent on most of the 150,000, reduced slightly by the deduction for half of self employment tax.

Just the self employment component alone can exceed 20,000, separate from income tax. That is why entity choice focuses so heavily on payroll tax.

Why Many Owners Start As LLC Then Elect S Later

The LLC gives liability protection and simple administration at lower income levels. When profit grows into the six figures, the self employment tax load becomes heavy enough that an S election often enters the conversation.

If you are the kind of entrepreneur who prefers to stay focused on operations and outsource the complexity, it is worth reviewing our page for business owners, which outlines how ongoing advisory can manage these transitions without disrupting cash flow.

Where S Corporations Create Real Savings

An LLC can elect to be taxed as an S corporation by filing Form 2553. Legally you may still be an LLC under state law, but for federal and California income tax purposes you are treated as an S corporation.

Reasonable Salary Versus Distribution

The core S strategy is splitting total business profit into

• W 2 wages subject to payroll taxes, and
• Shareholder distributions not subject to self employment tax.

The IRS expects owner employees to pay themselves reasonable compensation for the work they perform. That principle appears throughout IRS Publication 15 for employers and related guidance. Underpaying salary to dodge payroll tax is a classic audit trigger.

Example: David runs a consulting practice through an S elected LLC. The company nets 240,000 after expenses before owner compensation.

• He pays himself 120,000 as W 2 wages, supported by market data for his role.
• The corporation pays employer payroll taxes on the 120,000.
• The remaining 120,000 passes through as S profit, not subject to self employment tax.

Compare that to a pure LLC where the full 240,000 would be exposed to the 15.3 percent self employment layer. Saving that tax on 120,000 can easily be 18,000 plus per year. Against that, you must weigh payroll costs, extra filings, and California franchise minimums.

Interaction With The QBI Deduction

For eligible service businesses under the income thresholds, both default LLCs and S corporations can qualify for the 20 percent QBI deduction. However, in higher income ranges, W 2 wage and depreciable property tests come into play. S owners who structure reasonable salaries may preserve more QBI benefit than sole proprietors, depending on the mix of wages and profit. Section 199A is technical enough that alignment with tax planning services is essential once your taxable income approaches the phase out bands.

At this stage many owners ask whether a C corporation would be simpler. The answer depends on how soon you need to pull cash out of the business, how fast you are growing, and your exit strategy.

When A C Corporation Makes More Sense

The 2018 law set a flat corporate income tax rate. That stability made C corporations more attractive for certain high growth or capital intensive businesses that reinvest profit rather than distributing it.

The Double Tax Tradeoff

In a C corporation, profits are taxed at the corporate level. When those after tax profits are paid to you as dividends, they show up again on your personal return, usually at long term capital gain or qualified dividend rates.

Example: A C corporation in California earns 500,000 of taxable income and pays federal corporate tax plus California corporate tax. The remaining cash is either reinvested in the business or distributed as dividends later. If distributed, you will owe personal level tax on those dividends. Compare that to an S corporation where virtually all 500,000 flows through once to your personal return.

The flip side is that C corporations can sometimes smooth income across years, stock compensation, and investor expectations more easily, particularly for startups. They also avoid certain Section 199A limits by being fully out of the pass through regime.

Qualifying For Section 1202 Stock

One powerful but underused reason to consider a C corporation is the potential exclusion on the sale of qualified small business stock under Section 1202. If you meet the requirements, you may exclude up to the greater of 10 million of gain or 10 times your basis on the sale of stock. The rules are technical and require early planning, but they can dwarf annual payroll tax savings in the right fact pattern.

Red Flag Alert: Common Entity Mistakes That Trigger IRS Scrutiny

Certain patterns draw attention from the IRS, especially in S corporations and LLCs.

Underpaying Owner Salary In S Corporations

One of the fastest ways to end up in an employment tax exam is paying yourself a token W 2 wage like 24,000 while taking 200,000 of distributions. The IRS has repeatedly litigated this issue and often reclassifies distributions as wages, adding payroll tax, penalties, and interest.

We often see owners surprised that the payroll company will happily run any salary number you tell them. They are not signing your return. As the shareholder officer, you are responsible for setting a defensible compensation level based on duties, time devoted, and industry norms.

Using An LLC As Pure Asset Protection Without Tax Planning

Many online formation sites pitch LLCs as a magic liability shield. That part can be true, but if you ignore the tax side you may lock yourself into unnecessary self employment tax. Failing to consider an S election once profits reach six figures is a silent cost many owners pay for years.

Owners who are already juggling crews, invoices, and cash management may want a done for you layer. Our bookkeeping and payroll support packages are designed to integrate with entity strategy so the tax plan actually matches the numbers flowing through your accounts.

KDA Case Study: California Consultant Restructures And Cuts Payroll Tax

Alex is a 1099 software consultant based in San Diego. For several years he operated as a single member LLC reporting 220,000 to 260,000 of net profit on Schedule C. His prior preparer never raised the topic of entity elections, so Alex assumed he was already optimized after the 2018 law.

When he came to KDA, we rebuilt his 2023 numbers and showed that close to 34,000 of his annual tax bill was pure self employment tax. We walked through a restructuring model where his LLC would elect S status, and he would take a 140,000 salary based on prevailing rates for senior consultants, with the remaining 80,000 120,000 each year flowing as S distributions.

After implementing the change, Alex saw first year savings of about 13,000 in combined Social Security and Medicare tax, even after factoring in payroll costs and additional compliance. Our planning also tightened his estimated tax schedule and connected his structure to retirement planning so his cash savings were directed into a solo 401(k) rather than absorbed by lifestyle creep. On a 3,000 advisory fee, he achieved more than a four times cash on cash return in the first year alone.

Ready to see how we can help you? Explore more success stories on our case studies page to discover proven strategies that have saved our clients thousands in taxes.

How To Decide Between LLC, S Corporation, And C Corporation

Choosing the right entity is less about labels and more about how you expect to make money, pay yourself, and potentially exit.

Key Questions To Ask

• Do you plan to keep profit in the business or distribute most of it each year
• Is your income level stable, rising quickly, or highly volatile
• Do you intend to raise outside capital or remain closely held
• Is your business a specified service trade or business under Section 199A
• How important is simplicity versus ultimate tax efficiency

For a solo consultant netting 120,000 to 300,000 annually, an S election on top of an LLC is often the sweet spot once reasonable salary and payroll mechanics are dialed in. For a real estate investor holding long term rentals, a default LLC taxed as a partnership may be more appropriate. For a venture backed tech startup, C corporation status is usually mandatory for investor expectations and stock option planning.

Will This Trigger An Audit

A well supported S election with documented reasonable compensation is not, by itself, an audit trigger. What creates problems is aggressive salary suppression, sloppy recordkeeping, or ignoring required payroll filings. Likewise, operating as a C corporation is entirely acceptable if your facts align with that structure and you observe corporate formalities.

If you are trying to ballpark impact before making changes, running your projected profit through a tool like a self employment tax calculator or small business tax calculator can clarify the range of savings. Calculators provide a starting point, then a tailored plan refines the numbers around your actual mix of W 2 and 1099 income.

What About Multi Member LLCs And Partnerships

Everything above has focused on solo owners, but many California businesses have two or more members. In that case the default treatment is partnership taxation using Form 1065, with Schedule K 1s flowing to members.

Guaranteed Payments Versus Allocated Profit

In partnerships, owners can receive guaranteed payments, which look like salary substitutes, and also share in residual profit. Both create different tax effects. Guaranteed payments are typically subject to self employment tax for active partners, while certain limited partners may avoid that layer on distributive shares if they meet strict criteria.

The line between active and limited is not casual. The IRS and courts look at facts like hours, management authority, and how compensation is structured. For professional practices, regulators assume material participation almost by default.

Electing S Status From A Multi Member LLC

Multi member LLCs can also elect S corporation treatment if they qualify under shareholder limits. The same reasonable salary and payroll tax tradeoffs apply, but now you must coordinate wages and distributions for multiple people with possibly different roles.

For multi owner structures, we often combine tax planning with formal operating agreement updates so that cash distributions, buyouts, and death disability provisions work under the elected tax regime. These are classic scenarios where high quality entity formation and restructuring support saves conflict and tax cost later.

Fast Tax Fact: Deadlines And Elections You Cannot Miss

Entity choice is not entirely flexible after the fact. Elections must be timed correctly and coordinated with how you actually operate during the year.

Key Deadlines

• S corporation elections on Form 2553 are generally due two months and fifteen days after the beginning of the tax year for which you want S status, though late election relief is sometimes available.
• Changing a C corporation back to S status can be limited by five year waiting rules, making the initial choice important.
• California imposes its own minimum franchise tax and fee regime on LLCs and corporations, so cash flow modeling must include those fixed costs.

This information is current as of 6/16/2026. Tax law shifts frequently, so always confirm whether new federal or California guidance affects your decision before filing elections or restructuring.

Frequently Asked Questions About Comparing These Structures

What Is The Biggest Tax Difference Between LLC And S Corporation

The main difference is exposure to self employment tax. With a default LLC, nearly all profit is subject to that extra 15.3 percent layer. With an S corporation, only the W 2 wage portion is exposed, and the rest can avoid that tax if your salary is reasonable. Income tax rates can be similar because both are pass throughs.

When Does A C Corporation Beat An S Corporation

A C corporation can be better when you are reinvesting most profits, planning to raise outside capital, or aiming for a future stock sale potentially eligible for Section 1202 exclusion. In those cases, the double tax cost on dividends may be outweighed by growth, investor access, and long term gain planning.

Can I Switch Structures Later

Yes, but there are constraints and tax traps. Moving from LLC to S treatment is usually straightforward if planned early. Moving from S to C or back again requires more analysis around built in gains, accumulated adjustments accounts, and timing rules. It is far easier to structure correctly early than to unwind a decision after value has built up.

Book Your Tax Strategy Session

Entity choice is not a formality. It is a lever that can add or subtract five figures from your annual tax bill. If you are evaluating 2018 era changes and trying to decide how LLC, S corporation, or C corporation treatment fits your next five years, it is time to run real numbers instead of guessing. Click here to book your consultation now.