A business entity comparison calculator answers the question every business owner eventually asks: "Am I paying more tax than I need to because of my business structure?" The answer, for roughly 60% of sole proprietors earning over $80,000, is yes. Choosing between a sole proprietorship, LLC, S Corp, and C Corp isn't a one-time decision you set and forget — it's a lever that shifts your tax bill by $3,000 to $20,000+ per year depending on your profit level, salary split, and filing status.
This article doesn't rehash textbook definitions. Instead, we'll run three real scenarios at different income levels — $75,000, $150,000, and $300,000 — and show exactly which entity wins at each bracket, why, and by how much. We'll also cover the crossover points where switching structures starts making financial sense.
The Four Structures in 60 Seconds
Before we run numbers, here's the shortest possible summary of how each entity is actually taxed. Skip this if you already know the basics.
- Sole Proprietorship: All net profit flows to your personal return (Schedule C). You pay self-employment tax (15.3%) on 92.35% of every dollar, plus federal and state income tax. Simplest to set up, most expensive to maintain once profits climb past $60,000.
- Single-Member LLC:The IRS treats this as a "disregarded entity" — identical tax math to a sole proprietorship. The LLC provides liability protection, not tax savings. However, an LLC can elect to be taxed as an S Corp or C Corp, which is where the savings appear.
- S Corporation:You split income into a W-2 salary (subject to payroll tax) and a pass-through distribution (exempt from payroll tax). The IRS requires a "reasonable" salary, but everything above it avoids the 15.3% self-employment hit. Filed on Form 1120S.
- C Corporation:The business itself pays a flat 21% federal tax. When profits are distributed as dividends, shareholders pay dividend tax (0%, 15%, or 20% depending on income). This "double taxation" sounds harsh but can actually win at high income levels where individual rates hit 32–37%.
Scenario 1: The Freelancer at $75,000 Profit
Meet Sarah. She's a freelance graphic designer earning $75,000 in net profit after expenses, filing single, with a 5% state income tax rate. She has no other income. Let's compare her tax bill across all four structures.
Sole Proprietorship & LLC
Sarah's SE tax base is $75,000 × 92.35% = $69,263. Social Security tax: $69,263 × 12.4% = $8,589. Medicare: $69,263 × 2.9% = $2,009. Total SE tax: $10,597. After deducting half of SE tax ($5,299), her QBI deduction ($15,000), and the standard deduction ($15,750), her federal taxable income is roughly $38,951 — putting her firmly in the 12% bracket. Federal income tax: approximately $4,475. State tax at 5%: $3,750. Total tax bill: $18,822. Take-home: $56,178.
S Corporation (50% Salary = $37,500)
If Sarah elects S Corp status with a $37,500 reasonable salary, payroll taxes apply only to that salary: $37,500 × 15.3% = $5,738 in total payroll tax. Employer payroll ($2,873) is deducted by the corp, leaving a pass-through distribution of $34,627. The 20% QBI deduction on the distribution ($6,925) reduces her taxable income further. Federal income tax lands around $4,979. State tax: $3,606. Total tax:$14,323. Take-home: $60,677.
C Corporation
Under C Corp structure, corporate-level tax hits $75,000 × 26% (21% federal + 5% state) = $19,500. After-tax distributable income: $55,500. At this income level, qualified dividends fall in the 15% bracket: $55,500 × 15% = $8,325 in dividend tax. Total combined tax:$27,825. Take-home: $47,175. The double taxation clearly hurts here.
Verdict at $75,000
The S Corp saves Sarah $4,499 per yearcompared to her sole proprietorship. That's real money — but she needs to subtract $1,000–$2,000 in annual S Corp costs (payroll service, 1120S filing). Net benefit: roughly $2,500–$3,500 per year. Worth it, but not a slam dunk. The C Corp is the worst option by far at this income level, costing $9,003 more than the sole prop.
Scenario 2: The Consultant at $150,000 Profit
David runs a management consulting firm. He earns $150,000 in net profit, files single, lives in a state with 5% income tax. He sets his S Corp salary at $70,000 (47% of profit — well within the IRS safe harbor). Here's where the S Corp advantage really opens up.
| Tax Component | Sole Prop / LLC | S Corp | C Corp |
|---|---|---|---|
| SE / Payroll Tax | $21,194 | $10,710 | $0 |
| Federal Income Tax | $16,283 | $15,914 | $31,500 (corp) |
| Dividend Tax | — | — | $14,963 |
| State Tax | $7,500 | $7,232 | $7,500 (corp) |
| Total Tax | $44,977 | $33,856 | $53,963 |
| Take-Home | $105,023 | $116,144 | $96,037 |
The S Corp saves David $11,121 per year. Even after $1,500 in annual admin costs, he keeps an extra $9,621. Over five years, that's $48,105 — enough for a down payment on a rental property. The C Corp costs $9,000 more than even the sole prop at this level. We see this crossover consistently: the S Corp starts dominating once profits pass $80,000.
For a deeper dive on the S Corp math specifically, see our S Corp tax calculator with salary optimization tables at every percentage level.
Scenario 3: The Agency Owner at $300,000 Profit
Here's where things get interesting. Lisa owns a digital marketing agency earning $300,000 in net profit. She files married jointly and pays herself an $120,000 S Corp salary (40% of profit). Her state tax rate is 5%.
At $300,000, the sole prop SE tax hits $36,860 — approaching the Social Security wage base cap ($176,100 in 2025). The S Corp payroll tax on $120,000 salary is just $18,360. That's an $18,500 SE tax savings before we even consider income tax differences. After accounting for QBI deductions and income tax, the S Corp total tax comes to roughly $62,341 compared to $82,476 for the sole prop. The S Corp saves Lisa $20,135 per year.
But what about the C Corp? At $300,000, the picture shifts. Corporate tax: $300,000 × 26% = $78,000. Distributable: $222,000. Dividend tax at 15%: $33,300. Total: $111,300 — far more than either pass-through option. The C Corp only starts competing when profits exceed $500,000 and the owner plans to retain earnings rather than distribute them as dividends.
If you're comparing C Corp versus S Corp specifically, our C Corp vs S Corp calculator isolates that comparison with more granular inputs.
The Real Crossover Points
After running hundreds of combinations through our calculator, here are the general breakpoints we've found. These assume single filing, 5% state tax, and a 50% salary ratio for S Corp scenarios.
| Net Profit Range | Optimal Structure | Annual Tax Savings vs. Sole Prop |
|---|---|---|
| Under $40,000 | Sole Prop / LLC | $0 — S Corp costs eat the savings |
| $40,000 – $80,000 | S Corp (marginal) | $1,500 – $4,500 gross / $500 – $2,500 net after admin |
| $80,000 – $176,100 | S Corp (clear winner) | $5,000 – $15,000 |
| $176,100 – $500,000 | S Corp (strong winner) | $15,000 – $25,000 |
| $500,000+ | Consult CPA — C Corp may win if retaining earnings | Depends on distribution strategy |
The $176,100 threshold matters because that's the 2025 Social Security wage base. Above this level, the marginal SE tax savings from the S Corp decrease on the Social Security portion (since you'd cap out regardless). Medicare tax (2.9%, uncapped) still provides savings on every dollar above the salary level, which is why the S Corp continues to win at higher incomes.
Five Mistakes That Wipe Out Your Entity Tax Savings
Choosing the right structure is step one. Executing it properly is step two — and this is where we see people leave money on the table.
- Setting S Corp salary below market rate.Paying yourself $30,000 when your role commands $70,000 saves an extra $6,120 in payroll taxes — until the IRS reclassifies your distributions as wages. The penalty: back taxes, 20% accuracy penalty, and interest. Total exposure on $40,000 of reclassified distributions: $8,000–$12,000. Use the Bureau of Labor Statistics wage data to document your salary choice.
- Ignoring entity-specific administrative costs.S Corps require payroll processing ($500–$2,000/year), a separate 1120S tax return ($500–$1,500 for a CPA), state franchise fees, and registered agent fees. C Corps add a second level of tax filing on Form 1120. If your tax savings are only $2,000, half of that disappears into admin.
- Missing the QBI deduction on pass-through income.The 20% Section 199A deduction applies to S Corp distributions and sole prop profits (with limitations at high income). On $100,000 of qualifying income, that's a $20,000 deduction worth $4,400–$7,400 in tax savings. We've seen returns where this was left off entirely.
- Choosing C Corp without a retention strategy.A C Corp only wins when you plan to reinvest profits at the 21% corporate rate rather than distribute them. If you pull out everything as dividends, double taxation pushes your effective rate to 36–40% — higher than any pass-through structure.
- Failing to reassess as income changes.The optimal entity at $50,000 profit is not the optimal entity at $200,000. We've found that roughly 1 in 4 business owners hasn't reviewed their structure in 3+ years, even after doubling their revenue. Run this calculator annually or whenever your profit changes by more than 25%.
Which Structure Fits Your Situation?
Beyond the pure tax math, several non-tax factors influence the decision. Consider these before making a change.
- Do you need liability protection? Sole proprietorships offer zero personal asset protection. An LLC, S Corp, or C Corp creates a legal shield between your business debts and your personal assets. If liability matters (and it should for most service businesses), start with an LLC at minimum.
- Are you raising outside investment? C Corps are the standard for venture-backed startups. S Corps are limited to 100 shareholders, one class of stock, and no foreign owners. If equity fundraising is on your roadmap, C Corp is the only practical choice regardless of the tax implications.
- How much complexity can you handle?A sole proprietorship requires Schedule C attached to your personal return. An S Corp adds a separate business return, payroll processing, and quarterly filings. A C Corp doubles the filing burden. If you don't have a bookkeeper or CPA, the simplicity of a sole prop has genuine operational value.
- Do you plan to retain earnings in the business?If you reinvest most profits into growth (hiring, inventory, equipment), the C Corp's flat 21% rate may beat the 32–37% individual rates at high income levels. Use our business valuation calculator to model how retained earnings compound over time.
For business owners who need to estimate their quarterly payments after choosing a structure, our quarterly tax calculatorbreaks down when each payment is due and how much to set aside. And if you're specifically focused on understanding your LLC tax exposure, the LLC tax calculator provides a single-member vs. multi-member breakdown with state-by-state nuances.
Understanding your overall effective tax rate across all income sources is also essential — the entity structure only controls the self-employment tax portion, not your marginal bracket on ordinary income.
