A graphic designer I know was paying herself $120,000 a year through her single-member LLC. Every dollar of that profit hit her with the full 15.3% self-employment tax. That’s $18,360 a year before income taxes even entered the picture. Her CPA told her to elect S corp status. She did. Her self-employment tax bill dropped by roughly $7,000 annually. Same business, same revenue, same client list. Just a different tax election on a piece of paper.

That’s the S corp pitch in a nutshell, and it’s a real, legitimate tax advantage that saves small business owners billions of dollars collectively every year. But the details matter more than the headline, and I’ve watched plenty of people elect S corp status too early, too late, or for the wrong reasons. Getting it right requires understanding not just the upside but the rules, the costs, and the IRS’s very specific expectations.

What an S Corp Actually Is

An S corporation isn’t really a type of business entity. It’s a tax classification. This confuses almost everyone, and it’s the most important thing to understand before going further.

You don’t form an S corp. You form a corporation or an LLC under your state’s laws, and then you file Form 2553 with the IRS to elect S corporation tax treatment. The “S” refers to Subchapter S of the Internal Revenue Code, which allows certain corporations to pass their income through to shareholders’ personal tax returns instead of paying corporate tax.

A standard C corporation (Subchapter C) pays corporate income tax on its profits. Then, when those profits are distributed to shareholders as dividends, the shareholders pay tax again on their personal returns. That’s the “double taxation” you’ve heard about. An S corp avoids this: the company’s income, deductions, and credits flow through to the shareholders, who report them on their individual returns. The corporation itself generally doesn’t pay federal income tax.

The IRS S corporations page lays out the basic framework, but here’s the practical translation: an S corp is a way to run a business that looks like a corporation for legal purposes but gets taxed more like a partnership or sole proprietorship.

The Self-Employment Tax Advantage

This is why most small business owners care about S corps. And it’s a genuinely big deal.

If you’re a sole proprietor or a single-member LLC (which is taxed as a sole proprietorship by default), every dollar of net profit is subject to self-employment tax: 12.4% for Social Security (on income up to $168,600 in 2025) plus 2.9% for Medicare, totaling 15.3%. On $150,000 of profit, that’s $22,950 in self-employment tax alone, before federal and state income taxes.

With an S corp, you split your business income into two buckets: salary and distributions. You pay yourself a “reasonable salary” as an employee of the S corp, and that salary is subject to payroll taxes (the equivalent of self-employment tax, but split between employer and employee). Any remaining profit is distributed to you as the shareholder, and those distributions are NOT subject to self-employment or payroll taxes.

Back to that graphic designer. Her business nets $120,000. As an S corp, she pays herself a $70,000 salary (which her CPA determined was reasonable for her role and market). The remaining $50,000 comes as a shareholder distribution. She pays payroll taxes on the $70,000 salary (roughly $10,710) but not on the $50,000 distribution. As a sole proprietor, she’d pay self-employment tax on the full $120,000 ($18,360). The S corp saves her about $7,650 in payroll-related taxes.

That savings compounds every single year. Over a decade, that’s $76,500 in tax savings from a paperwork change. You can see why CPAs get excited about this.

S Corp vs. LLC vs. C Corp

These three get thrown around interchangeably, and they’re fundamentally different things operating on different dimensions.

LLC (Limited Liability Company). This is a state-level legal structure. It provides liability protection (your personal assets are generally separate from business debts) and operational flexibility. By default, a single-member LLC is taxed as a sole proprietorship and a multi-member LLC is taxed as a partnership. But an LLC can elect to be taxed as an S corp or a C corp. The LLC is the container. The tax election is what goes inside it.

S Corp. A tax election, not a legal structure. You can be an LLC taxed as an S corp, or a corporation taxed as an S corp. Either way, you get the pass-through taxation and the self-employment tax advantage described above.

C Corp. The default tax treatment for a corporation. Profits are taxed at the corporate level (21% flat rate since the Tax Cuts and Jobs Act of 2017), and dividends are taxed again when distributed to shareholders. C corps make sense for businesses that plan to reinvest profits heavily, seek venture capital, or go public. They don’t make sense for most small businesses pulling all the profit out each year.

For a solo consultant, freelancer, or small service business generating $75,000 to $500,000 in annual profit, the most common structure is: form an LLC under state law, then elect S corp taxation with the IRS. You get liability protection from the LLC structure and tax savings from the S corp election. The SBA’s guide to business structures covers the legal side, while the tax considerations are an IRS matter.

The Reasonable Salary Requirement

Here’s where people get in trouble. The IRS requires S corp shareholder-employees to pay themselves a “reasonable salary” before taking distributions. You can’t pay yourself $10,000 and take $140,000 in distributions on $150,000 of profit. The IRS will come after you, and they’ve won repeatedly in Tax Court.

“Reasonable” means what someone in your role, in your industry, in your market would earn as an employee. A lawyer running a one-person firm billing $300,000 a year can’t claim a $40,000 salary is reasonable when junior associates at firms in the same city earn $80,000. The IRS looks at comparable salaries for your skill set, experience, and geographic area.

The landmark case here is Watson v. Commissioner (2012), where the Tax Court ruled that an accountant’s S corp paying him $24,000 on $200,000+ of net income was unreasonable. The IRS reclassified a portion of his distributions as wages and assessed back payroll taxes plus penalties.

Sources the IRS and courts reference when evaluating reasonable compensation include Bureau of Labor Statistics wage data, job postings for comparable roles, and industry compensation surveys. The IRS guidance on reasonable compensation is deliberately vague on exact numbers, which gives some flexibility but also means there’s no bright-line rule to hide behind.

A common rule of thumb among CPAs: set your salary at roughly 60% of net profit for service businesses, and adjust based on industry data. If your business requires significant equipment or real estate (where the asset generates income beyond your personal labor), a lower salary percentage might be defensible. But for a consultant whose only asset is their brain, the IRS expects salary to represent the bulk of the income.

How to Elect S Corp Status

The process is mechanical, but timing matters.

Step one: have an eligible entity. You need either a domestic corporation or an LLC that’s eligible for S corp treatment. The entity must have no more than 100 shareholders, all shareholders must be U.S. citizens or resident aliens (no foreign shareholders), and the company can only have one class of stock. Certain types of entities (banks, insurance companies, international sales corporations) are ineligible.

Step two: file Form 2553. This is the Election by a Small Business Corporation form. All shareholders must sign it. For the election to take effect for the current tax year, you generally need to file by March 15 (for calendar-year taxpayers). If you miss the deadline, the election kicks in the following year, unless you can demonstrate reasonable cause for the late filing.

The March 15 deadline is absolute for intentional elections, but the IRS has been relatively lenient with late election relief under Revenue Procedure 2013-30. If you intended to be an S corp from day one but your accountant dropped the ball, you can often file a late election with a reasonable-cause statement. I’ve seen this work multiple times, but don’t count on it.

Step three: set up payroll. Once you’re an S corp, you’re an employer. You need an EIN (if you don’t already have one), a payroll system, quarterly payroll tax filings (Form 941), annual W-2s for yourself, and workers’ compensation insurance in most states. This is where the cost and complexity come in.

Step four: file the right tax return. S corps file Form 1120-S annually. Each shareholder receives a Schedule K-1 showing their share of the company’s income, deductions, and credits, which they report on their personal return. The 1120-S is due March 15 (or the 15th day of the third month after the fiscal year ends), and late filing penalties are $220 per shareholder per month. Those penalties add up fast if you forget.

The Costs of Running an S Corp

The tax savings are real, but they aren’t free. Running an S corp costs more than running a simple sole proprietorship or single-member LLC.

Payroll processing. You’ll need payroll software or a payroll service. Gusto, ADP, and similar services charge $40 to $80 per month for a single employee (you). That’s $480 to $960 per year.

Tax preparation. A Form 1120-S is more complex than a Schedule C. Expect to pay your CPA $800 to $2,000 more per year for the S corp return on top of your personal return. Some CPAs charge $1,500 to $3,000 for the full package.

State fees. Many states impose franchise taxes or minimum taxes on S corps. California charges a minimum $800 franchise tax annually, regardless of income. New York City has its own corporate tax that applies to S corps. These vary wildly by state.

Bookkeeping. S corps require cleaner books than sole proprietorships. You’ll want accounting software and possibly a bookkeeper, especially as revenue grows.

Total additional cost of S corp status: roughly $2,000 to $5,000 per year for a simple one-person operation. If your self-employment tax savings don’t exceed that cost by a comfortable margin, the S corp election isn’t worth the hassle.

When the S Corp Election Makes Sense

The breakeven point varies, but most CPAs suggest considering S corp status when your net self-employment income consistently exceeds $50,000 to $60,000 per year. Below that, the administrative costs eat up most or all of the tax savings.

The sweet spot is net income between $80,000 and $400,000 for a single-owner service business. The self-employment tax savings are meaningful, the administrative burden is manageable, and the reasonable salary analysis is relatively straightforward.

Above $400,000 to $500,000, you might want to explore C corp taxation instead, particularly if you’re reinvesting significant profits into the business. The 21% flat corporate rate can be advantageous when combined with strategies to defer or minimize dividend taxation. Your CPA should model both scenarios.

S corp doesn’t make sense for everyone. If your business has foreign shareholders, you can’t elect. If you want multiple classes of stock to attract investors, S corp won’t allow it. If you’re a real estate investor who benefits from passive loss treatment, S corp can create complications. And if you’re just getting started and your income is unpredictable, the overhead of maintaining an S corp during a year when you only net $20,000 is painful.

The IRS’s overview of business structures provides a comparison tool, but it’s surface-level. For anything beyond the basics, get a CPA who specializes in small business taxation. The $500 you spend on a consultation could save you tens of thousands in the right scenario, or stop you from creating an expensive structure you don’t need.

Common S Corp Mistakes

Skipping payroll entirely. Some S corp owners take all their income as distributions and never run payroll. This is a red flag the IRS specifically watches for. If you’re an S corp shareholder who performs services for the company, you must be on payroll. No exceptions.

Setting salary too low. Related to the above. Paying yourself $30,000 when comparable professionals earn $90,000 invites an audit. The IRS can reclassify distributions as wages and assess back taxes, penalties, and interest.

Missing the S corp filing deadline. The Form 1120-S is due March 15, a full month before personal returns. Miss it, and you’re looking at $220 per shareholder per month in penalties. For a two-shareholder S corp that files six months late, that’s $2,640 in penalties on a return that might show zero tax due.

Forgetting state-level requirements. Your S corp election is a federal tax matter. Many states honor it automatically, but some don’t. A few states (like New Hampshire and Tennessee, historically) tax S corp income at the entity level. California’s $800 minimum franchise tax applies regardless of your federal election. Check your state’s requirements.

Not maintaining corporate formalities. S corps that are organized as corporations (not LLCs) need to maintain corporate minutes, hold annual meetings, and keep records. Failure to do so can jeopardize your liability protection in a lawsuit. An LLC taxed as an S corp has more flexibility on formalities, which is one reason the LLC + S corp election combo is so popular.

Can a single-member LLC elect S corp status?

Yes. This is actually the most common path to S corp taxation for solo business owners. You form a single-member LLC under state law, then file Form 2553 with the IRS to elect S corp tax treatment. You get the liability protection of the LLC, the operational flexibility of the LLC structure, and the tax benefits of S corp classification. You’ll need to put yourself on payroll and file Form 1120-S annually.

How much does an S corp save on taxes?

It depends on your net income and reasonable salary. A rough estimate: if your business nets $150,000 and you set your salary at $80,000, you’d save approximately $10,710 in self-employment taxes on the $70,000 in distributions (15.3% of $70,000). Subtract the additional administrative costs ($2,000 to $5,000 per year), and your net savings are roughly $5,700 to $8,700 annually. The higher your net income above a reasonable salary, the more you save.

What is the deadline to file Form 2553?

For the election to be effective for the current tax year, Form 2553 must be filed by March 15 for calendar-year taxpayers (or by the 15th day of the third month of the tax year for fiscal-year taxpayers). You can also file within two months and 15 days of the start of the tax year. If you miss the deadline, the election takes effect the following year unless you qualify for late election relief under Revenue Procedure 2013-30.

Can an S corp have more than one owner?

Yes, up to 100 shareholders. All shareholders must be U.S. citizens or resident aliens, and the company can only have one class of stock (though voting and non-voting shares are permitted). Spouses and certain family members can be treated as a single shareholder for the 100-shareholder limit. If you need foreign shareholders or multiple stock classes, you’ll need a C corp instead.

What's the difference between an S corp and an LLC taxed as an S corp?

Legally, they’re different entities. A corporation has shareholders, a board of directors, and formal governance requirements. An LLC has members, a more flexible operating agreement, and fewer formalities. But when both elect S corp taxation, the federal tax treatment is essentially identical: pass-through income, payroll for shareholder-employees, and distributions that avoid self-employment tax. The LLC version is generally simpler to operate and maintain, which is why most small business owners prefer it.