C-Corp vs S-Corp vs LLC: How to Choose in 2026

The structure question is the first big tax decision every US founder makes. Get it right and you'll save tens of thousands annually. Get it wrong and you'll either overpay tax (sole-prop on $200k profit) or paint yourself into a corner (C-corp when you can't easily distribute).

This guide compares the four main options for federal tax purposes. State rules vary; we cover federal here.

Quick comparison

Federal tax mechanics in 60 seconds

Sole proprietor / single-member LLC (default): business income flows to your Schedule C on Form 1040. Pay regular federal income tax + 15.3% self-employment tax on net SE earnings (deduct half as adjustment).

Multi-member LLC (default): files Form 1065, issues K-1 to each member. Each member reports on personal 1040 + pays 15.3% SE tax on their share (limited partner exception narrow).

S-corporation: files Form 1120-S. No entity-level federal income tax. Issues K-1 to shareholders. Critical: shareholder-employees must take "reasonable compensation" as W-2 wages subject to FICA. Profit above that flows as K-1 distribution NOT subject to FICA — that's the savings.

C-corporation: files Form 1120, pays 21% flat federal corporate income tax. Distributes after-tax profit as dividends taxed again at shareholder level (qualified div: 0%/15%/20% + 3.8% NIIT for high earners). "Double taxation."

When each makes sense

Stay sole prop / SMLLC if:

• Net profit under ~$80,000 (S-corp savings don't outweigh payroll/CPA cost)
• Side hustle or new business proving product-market fit
• Simple operations, single owner, no plans to raise external capital
• Clean exit to W-2 job possible

Convert to S-corp if:

• Net profit consistently $80,000+ per year
• One or more US-individual shareholders (≤100 total)
• One class of stock (no preferred / two-class issues)
• You can pay yourself a "reasonable" W-2 salary
• Industry is not banking, insurance, or international

Choose C-corp from the start if:

• Raising venture capital (VCs require Delaware C-corp)
• Want QSBS Section 1202 gain exclusion (up to $10m / 10× basis tax-free after 5 years)
• Have foreign owners or entity owners
• Need preferred stock or multiple classes
• Plan to retain large profits for reinvestment (retain at 21% vs flow-through to top brackets)

Multi-member LLC (taxed as partnership) if:

• 2+ founders or partners
• Want pass-through treatment with the LLC umbrella (vs. forming a real partnership)
• Don't yet need C-corp's QSBS or VC structure
• Special allocations needed (LLC operating agreement allows allocations beyond pro-rata)

The S-corp election: how the math works

S-corp election is the single biggest tax planning win for profitable owner-managed businesses earning $80k+ annually. Here's the math at $150,000 net business income.

As sole proprietor / SMLLC

As S-corporation (electing reasonable comp of $80,000)

Less ~$2,000–$3,000 of payroll/CPA cost overhead, net annual savings ~$6,000. Compounds yearly.

The savings scale roughly linearly with profit above the W-2 wage. At $300k profit, S-corp can save $15k+ annually.

Reasonable compensation — the audit trap

The IRS requires S-corp shareholder-employees to pay themselves "reasonable compensation" — what someone would be paid for the same role at arm's length. Payroll services like Gusto, RCReports, and AccountsOS provide industry benchmarks.

The IRS audits S-corps that take little or no W-2 (taking it all as K-1 distribution to dodge FICA). They reclassify some K-1 as wages, charge back FICA + interest + penalties.

Rough rule of thumb: pay yourself W-2 wages at the rate you'd pay an arm's-length employee doing the same work, then take the rest as distributions. For a one-person consultancy, that's typically ~$70,000–$120,000 W-2 plus distributions.

Why VC-backed startups are always Delaware C-corps

VCs require:

• Preferred stock (Series Seed, A, B...) — only C-corps support multiple classes
• Easy QSBS qualification for early-stage investments
• Predictable corporate governance (Delaware courts have decades of case law)
• Foreign and entity investors accepted (S-corp can't have either)
• IPO-ready structure

If you're raising more than $1m of priced equity, you're a Delaware C-corp. The tradeoff (21% corporate tax + double taxation on dividends) is irrelevant pre-profitability and offset by QSBS at exit.

Beneficial Ownership Information (BOI) — new for 2024+

Since 1 January 2024, most US LLCs and corporations must file Beneficial Ownership Information with FinCEN. New entities: report within 30 days of formation. Existing entities (formed before 2024): originally due 1 January 2025, with ongoing legislative and court challenges — check current status.

Failure to file: civil penalty up to $591/day; criminal penalty up to $10,000 + 2 years prison. (Penalties have been temporarily suspended pending litigation in early 2025; verify before relying.)

Switching structures later

You can convert. The most common paths:

• Sole prop → SMLLC: file LLC paperwork in your state. Federal tax: no change (default disregarded entity).
• SMLLC → S-corp: file Form 2553 (need to be eligible). Effective for tax year if filed within 75 days. Federal taxation flips from Schedule C to Form 1120-S.
• LLC → C-corp: file Form 8832 to elect corporate taxation, or convert to corporation under state law (cleaner for VC).

The reverse (C-corp → S-corp → LLC) is harder and often triggers built-in gains tax or other one-shot taxes. Plan upfront where you can.

State tax — the elephant in the room

Federal is just one layer. State income tax, state franchise tax, sales tax and local tax can dramatically change the math:

• California: 8.84% corporate rate, $800 minimum LLC tax, complex S-corp rules
• Delaware: $300 LLC franchise tax, $175+ corporate franchise tax (sliding scale)
• Texas: no state income tax but franchise/margin tax above ~$2.47m revenue
• New York: 6.5% corporate tax, separate NYC tax

AccountsOS covers federal at launch. State coverage is in development — for state-specific planning, work with a state-licensed CPA in your jurisdiction.

How AccountsOS helps US founders

AccountsOS is live for US federal tax. Finn:

• Tracks Schedule C income, deductions and quarterly estimated tax for sole props/SMLLCs
• Runs S-corp payroll with reasonable compensation benchmarks
• Tracks K-1 distributions, retained earnings and basis
• Generates Form 1120-S and Form 1120 schedules
• Maintains Form 1099-NEC issuance for contractors $600+
• Tracks BOI filing status with FinCEN

State coverage is roadmapped — for now, Finn flags state-level questions and recommends a state CPA.

Try AccountsOS free or read about AccountsOS in the United States.

Related reading

• Self-employment tax explained
• S-corp election: when does it pay off?
• Quarterly estimated tax: avoiding the underpayment penalty
• QSBS Section 1202: $10m tax-free for founders