First: LLC and S-Corp are not the same type of thing
Before comparing them, it helps to understand that LLC and S-Corp operate on two different levels:
- LLC is a legal structure — it's how your business is registered with your state.
- S-Corp is a tax election — it's how the IRS taxes your business income.
This means they're not mutually exclusive. In fact, the most common setup for profitable small businesses is: an LLC that elects to be taxed as an S-Corp. You get the legal simplicity of an LLC combined with the tax advantages of S-Corp treatment.
When people say "should I be an LLC or an S-Corp," they're usually really asking: "should my LLC elect S-Corp tax treatment?" Because the LLC structure itself stays the same — only the tax treatment changes.
How each is taxed — and why it matters
Default LLC taxation (no S-Corp election)
By default, if you're the only owner of an LLC, the IRS treats all your business profit as your personal income. Every dollar of net profit is subject to:
- Self-employment tax: 15.3% (covers Social Security and Medicare)
- Federal income tax: based on your total income bracket
- State income tax: varies by state
The self-employment tax applies to all your net profit. There's no way around it under default LLC taxation.
S-Corp taxation (after electing S-Corp status)
With an S-Corp election, your income is split into two parts:
- Your salary — subject to payroll taxes (same as self-employment tax), reported on a W-2
- Owner distributions — the remaining profit passed through to you, not subject to self-employment tax
The tax saving comes from that second category. Distributions avoid the 15.3% self-employment tax entirely. The more profit you take as distributions rather than salary, the more you save — but the IRS requires your salary to be "reasonable," so there's a limit to how far you can take this.
A real example with numbers
Let's say your LLC nets $100,000 in profit this year.
| Default LLC | LLC taxed as S-Corp | |
|---|---|---|
| Net profit | $100,000 | $100,000 |
| Owner salary | N/A | $60,000 |
| Distributions | N/A | $40,000 |
| Self-employment / payroll tax | $14,130 (15.3% of 92.35% of $100K) | $9,180 (15.3% of the $60K salary — employer and employee shares) |
| Estimated SE tax savings | — | ~$4,950/year |
| Additional S-Corp costs (payroll, tax return) — assumed for this example | — | ~$1,500–$3,000/year |
| Approximate net savings | — | ~$1,950–$3,450/year |
The actual savings depend on your salary amount, state taxes, and the specific costs of running payroll and filing an S-Corp return. It also leaves out the QBI deduction: an S-Corp owner's salary is not qualified business income, so a higher salary can mean a smaller QBI deduction. Always run the numbers with a CPA for your situation before making the election.
When does an S-Corp make sense?
There is no IRS income threshold for electing S-Corp status. Whether it saves money depends on how much of your profit is left after paying yourself a reasonable salary, your state's taxes and fees, and the added cost of payroll and a separate business return. Compare those numbers for your own situation — ideally with a tax professional — before filing Form 2553.
The real costs of running an S-Corp
The tax savings are real — but so are the additional costs and requirements. Before electing S-Corp status, understand what you're taking on:
- Separate business tax return (Form 1120-S) — Due by the 15th day of the 3rd month after the tax year ends (March 16, 2026 for calendar-year 2025, because March 15 falls on a Sunday; March 15, 2027 for calendar-year 2026). More complex than a Schedule C, and many owners pay a tax professional to prepare it.
- Payroll setup and quarterly filings — You must run payroll for yourself as an employee, file quarterly payroll tax returns (Form 941), and issue yourself a W-2 at year end. Many owners use a payroll service, which adds cost.
- More accounting work — With payroll, quarterly filings, and a separate business return, your bookkeeping becomes more demanding. Factor in CPA costs accordingly.
- Reasonable salary scrutiny — The IRS watches for S-Corp owners who pay themselves unreasonably low salaries to maximize distributions. Getting this wrong can trigger audits and penalties.
The IRS has successfully challenged S-Corp owners who paid themselves below-market salaries to avoid payroll taxes. Your salary must be comparable to what you'd pay an employee to do the same work. A CPA can help you establish a defensible salary for your industry and income level.
Four rules to know before you elect
- Reasonable compensation comes first. The IRS says an S corporation must pay reasonable compensation to a shareholder-employee for services before making non-wage distributions, and it can reclassify distributions as wages. Factors it lists include training and experience, duties, time devoted to the business, and what comparable businesses pay. See running an S-Corp.
- Salary is not QBI. Amounts received as reasonable compensation from an S corporation are not qualified business income, so moving profit into salary can reduce your QBI deduction. Your K-1 share of business income can still be QBI. See the QBI deduction.
- Form 1120-S has a real deadline. It is due by the 15th day of the 3rd month after the tax year ends (March 15, 2027 for calendar-year 2026). Form 7004 generally gives an automatic 6-month extension to file. The late-filing penalty, per shareholder for each month or part of a month (up to 12 months), is $255 for calendar-year 2025 returns and $260 for calendar-year 2026 returns (Rev. Procs. 2024-40 and 2025-32), plus more if tax is due.
- Late elections can sometimes be fixed. The Form 2553 instructions describe relief under Rev. Proc. 2013-30, generally available within 3 years and 75 days of the intended effective date if there was reasonable cause and all affected shareholders reported consistently.
Side-by-side comparison
| Feature | Default LLC | LLC with S-Corp election |
|---|---|---|
| Self-employment tax | On all net profit | Only on salary portion |
| Payroll required | No | Yes — owner must be on payroll |
| Separate business tax return | No (Schedule C on personal return) | Yes — Form 1120-S (due the 15th day of the 3rd month after year end) |
| Complexity | Low | Medium to high |
| Annual compliance cost | Lower | Higher (payroll and a separate business return) |
| Eligibility restriction | None (any owner) | No nonresident alien shareholders; max 100 shareholders; one class of stock |
| Best for | Owners who prefer simplicity, or whose savings wouldn't cover the added costs | Owners whose profit is consistently well above a reasonable salary, willing to handle added compliance |
How to make the S-Corp election
If you've decided an S-Corp election makes sense, here's what's involved:
- File Form 2553 with the IRS — this is the official S-Corp election form. To apply to the current year, it generally must be filed no more than 2 months and 15 days after the beginning of the tax year (for a new LLC, after it first has shareholders, acquires assets, or begins doing business).
- Set up payroll — use a payroll service (Gusto, ADP, QuickBooks Payroll) to run your salary as an employee. This handles withholding, quarterly filings, and W-2 generation.
- Work with a CPA — given the complexity, an S-Corp is rarely a DIY situation. A CPA can determine your reasonable salary, file Form 1120-S, and help you stay compliant year after year.
If your LLC's profit is consistently well above a reasonable salary for your work and you're planning to keep growing, an S-Corp election is worth a conversation with a CPA. The savings are real — but so are the requirements. Don't make this decision based on a general article alone; the right answer depends on your specific income, salary, and state.