C-Corp vs. S-Corp: Complete Tax Comparison for Small Business Owners in 2025

By Yarik Yarosh, CPA ·September 5, 2026 ·8 min read

Written by Yarik Yarosh, CPA (US & Canada) September 5, 2026 · FL CPA license AC61704 · CPA Ontario

The choice between C-Corp and S-Corp taxation is one of the most consequential decisions a business owner makes. Both structures provide liability protection, but they differ fundamentally in how income is taxed. A C-Corp pays entity-level tax at a flat 21% rate (made permanent by the TCJA), and distributions to shareholders are taxed again as qualified dividends (15-20%), creating “double taxation.” An S-Corp is a pass-through entity: no entity-level tax, income flows through to the shareholder’s personal return, taxed once at individual rates (10-37%). However, S-Corp owners who work in the business must pay themselves a “reasonable” W-2 salary subject to FICA (15.3%), while C-Corp owner-employees can set their salary with more flexibility and retain earnings in the corporation at the 21% rate. The optimal choice depends on the business’s net income, the owner’s personal tax bracket, how much income is distributed vs. retained, and whether the owner plans to sell the business (where the QSBS exclusion under IRC 1202 provides a massive advantage to C-Corps).

✓Key takeaway

Side-by-side comparison:

Factor	C-Corp	S-Corp
Entity-level tax	21% flat	None (pass-through)
Distribution tax	15-20% qualified dividends (double tax)	Not taxed (already taxed at individual level)
Individual tax on business income	Only on salary/dividends	10-37% on all pass-through income
FICA on owner salary	15.3% (employer + employee)	15.3% (employer + employee)
FICA on distributions	None	None
Reasonable compensation required?	Less scrutiny	Yes (IRS actively audits)
QBI deduction (IRC 199A)	Not available	20% deduction on QBI (permanent under OBBBA)
QSBS exclusion (IRC 1202)	Yes (up to $10M or 10x basis excluded from capital gains)	Not available
Retained earnings	Taxed at 21% (no individual tax until distributed)	Taxed at individual rate regardless
Net operating losses	Carried forward at entity level	Pass through to shareholders
State taxes	May face separate state corporate tax	Pass-through in most states
Maximum shareholders	Unlimited	100
Classes of stock	Unlimited	One class (economic rights identical)

When C-Corp wins:

Scenario	Why C-Corp Is Better
Planning to sell the business (QSBS)	Up to $10M in capital gains excluded from tax
Retaining significant earnings for growth	21% corporate rate vs. 37% individual rate
Seeking venture capital or going public	Preferred stock, multiple classes, unlimited shareholders
Very high income ($500K+) with low distributions	21% rate on retained earnings vs. 37% personal rate

When S-Corp wins:

Scenario	Why S-Corp Is Better
Distributing most/all income to owners	Single layer of tax at individual rates
Owner works in the business	FICA savings on distributions
Income under $400K (QBI deduction available)	20% QBI deduction reduces effective rate
Eventual sale (asset sale)	Single tax at individual rates, no double taxation
Passive investment income	No C-Corp built-in gains tax or passive income penalties

How do the tax numbers compare at different income levels?

Hypothetical example

Round numbers. For current guidance, see IRS corporation guidance. A single-owner business. Net income before owner compensation: $300,000. Owner needs $200,000 for personal expenses.

Scenario 1: S-Corp (salary $100,000, distribution $200,000)

Item	Amount
S-Corp net income	$300,000
Owner salary	($100,000)
Net income after salary	$200,000
Employer FICA	$100,000 x 7.65% = $7,650
S-Corp taxable income (K-1 to owner)	$200,000 - $7,650 = $192,350
Owner’s total taxable income	$100,000 salary + $192,350 K-1 = $292,350
QBI deduction (20% of $192,350)	($38,470)
Adjusted taxable income	$253,880
Federal income tax (after standard deduction $15,000)	~$51,000
Employee FICA	$100,000 x 7.65% = $7,650
Total tax	~$51,000 + $7,650 + $7,650 = $66,300
Effective rate on $300,000	22.1%

Scenario 2: C-Corp (salary $100,000, dividend $131,000)

Item	Amount
C-Corp gross income	$300,000
Owner salary	($100,000)
Employer FICA	($7,650)
Taxable corporate income	$192,350
Corporate tax (21%)	($40,394)
After-tax corporate income	$151,956
Dividend to owner	$131,000 (enough for $200,000 total after salary)
Retained in C-Corp	$20,956

Tax Layer	Amount
Corporate tax (21%)	$40,394
Owner’s income tax on salary ($100,000)	~$14,000
Owner’s FICA (employee)	$7,650
Employer FICA	$7,650
Qualified dividend tax ($131,000 x 15%)	$19,650
NIIT on dividends (3.8%, if MAGI > $200K)	$131,000 x 3.8% = $4,978
Total tax (all levels)	$40,394 + $14,000 + $7,650 + $7,650 + $19,650 + $4,978 = $94,322
Effective rate on $300,000	31.4%

Comparison:

Factor	S-Corp	C-Corp	Difference
Total tax	$66,300	$94,322	S-Corp saves $28,022
Cash to owner	~$200,000	~$200,000	Same
Cash retained in business	$0	$20,956	C-Corp retains more
Effective rate	22.1%	31.4%	S-Corp is 9.3% lower

The S-Corp wins by $28,022/year when distributing most income. The C-Corp’s double taxation is expensive.

But: The QSBS significant advantage If the business is eventually sold for $5,000,000:

Factor	S-Corp	C-Corp (QSBS Eligible)
Sale price	$5,000,000	$5,000,000
Basis	$100,000	$100,000
Gain	$4,900,000	$4,900,000
QSBS exclusion (IRC 1202)	Not available	$4,900,000 excluded (under $10M cap)
Federal tax on sale	$4,900,000 x 20% + 3.8% NIIT = $1,166,200	$0
Lifetime tax savings from QSBS		$1,166,200

The QSBS exclusion saves $1,166,200 on a $5M exit. This dwarfs the annual S-Corp tax savings ($28,022/year x 10 years = $280,220). For a business that will be sold for a significant amount, the C-Corp with QSBS can be the better long-term choice despite the annual double taxation disadvantage.

QSBS requirements:

Requirement	Details
C-Corp only	S-Corps do not qualify
Gross assets under $50M	At and immediately after stock issuance
Held for 5+ years	Must hold the stock for at least 5 years
Active business (80% of assets)	At least 80% of assets used in active trade or business
Original issuance	Stock must be acquired at original issuance (not purchased from another shareholder)
Excluded industries	Professional services (law, accounting, health, consulting), banking, insurance, farming, hospitality

Many tech startups, product companies, and manufacturing businesses qualify for QSBS. Professional service firms (including CPA firms, law firms, and consulting practices) do NOT qualify.

The optimal dual strategy: Some business owners start as an S-Corp (for the annual FICA and single-taxation advantage), then convert to a C-Corp when they are planning an exit (to qualify for QSBS). The conversion must occur at least 5 years before the sale, and the business must meet QSBS requirements throughout the holding period. This strategy combines the annual S-Corp savings with the eventual QSBS exclusion.

Illustrative numbers only, not a real client and not advice for your facts.

What is double taxation and how does it affect C-Corp owners?

A C-Corporation pays federal income tax at a flat 21% rate on its taxable income, and when the corporation distributes after-tax profits as dividends to shareholders, those dividends are taxed again at the shareholder level. Qualified dividends are taxed at preferential rates (0%, 15%, or 20%), but the combined effective rate still exceeds the rate on pass-through income in most cases. Strategies to mitigate double taxation include paying reasonable salaries and bonuses to owner-employees (deductible by the corporation), maintaining an accountable plan for expense reimbursements, and retaining earnings for legitimate business growth rather than distributing them. The accumulated earnings tax (IRC 531) imposes a 20% penalty on earnings retained beyond the reasonable needs of the business, so indefinite retention is not a free strategy.

How does choosing the wrong entity structure affect my taxes?

The wrong entity can cost thousands in unnecessary taxes annually. A sole proprietor earning $120,000 pays roughly $17,000 in self-employment tax; an S-Corp paying a $70,000 reasonable salary saves approximately $7,650 in FICA on the remaining $50,000. Conversely, an S-Corp for a business earning $40,000 creates more compliance cost (payroll, separate return) than the FICA savings justify. A C-Corp creates double taxation on distributions unless the owner takes all profits as salary, which maximizes FICA. Switching later is possible but can trigger tax consequences: converting a C-Corp to an S-Corp subjects built-in gains to a 5-year recognition period.

Related guides:

SaaS Entity Structure: LLC, S-Corp, or C-Corp for Software Companies
C-Corp vs. S-Corp: When a C-Corporation Makes Sense for a Small Business
C-Corp vs. S-Corp: Tax Rates, Double Taxation, QSBS, and Which Structure Wins
C-Corp vs S-Corp for Small Businesses: Tax Comparison and When Each Makes Sense

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Cite this page

Yarik Yarosh, CPA. "C-Corp vs. S-Corp: Complete Tax Comparison for Small Business Owners in 2025." Blue Cloud CPA, September 5, 2026. https://bluecloudcpa.com/guides/small-business-c-corp-vs-s-corp-tax-comparison-2025

This guide is general information, not tax advice for your specific situation. Which points apply, and how, depends on your facts.