S-Corp vs Sole Proprietor

Q: Why would a sole prop elect S-Corp?

The single biggest reason is to reduce SE/FICA tax . A sole prop pays 15.3% on every dollar of profit (up to the SS wage base). An S-Corp owner pays FICA only on the W-2 reasonable-compensation portion; the remaining profit flows through as distributions, free of SE/FICA tax. On $100k of profit, that typically saves $7,000–$10,000 a year.

Sole prop is the cheap default — Schedule C, no payroll, no separate filings. S-Corp election trades annual overhead (the table below assumes $3,000) for SE-tax savings on the distribution portion of profit. On those assumptions the math turns positive at roughly $40k of net profit.

Side-by-side comparison

Feature	Sole Proprietor	S-Corp Election
Federal tax form	Schedule C on Form 1040	Form 1120-S + K-1 to owner
Self-employment / FICA tax base	100% of net SE earnings	W-2 reasonable comp portion only
Annual prep cost	$300–$600 (Sch C add-on)	$800–$2,500 (1120-S)
Payroll required?	No	Yes — Form 941 quarterly + W-2
Liability protection	No (personal assets exposed)	Yes (if LLC or Inc. shell)
Separate EIN	Optional	Required
QBI deduction (§199A)	20% of net SE income	20% of distribution portion only
Solo 401(k) employer base	Net SE earnings (after SE-tax adj.)	W-2 wages only
Reasonable-comp scrutiny	N/A	High — IRS audit target
State franchise / minimum tax	Usually none	$800+ (varies by state)

Break-even table by net profit

Assumes single-owner business, reasonable comp = 40% of profit, S-Corp overhead $3,000/yr, 2026 thresholds:

Net Profit	Sole Prop SE Tax	S-Corp FICA on $W-2 (40%)	Gross savings	Net (after $3k overhead)
$30,000	$4,239	$1,836	$2,403	−$597 (loss)
$50,000	$7,065	$3,060	$4,005	$1,005
$80,000	$11,304	$4,896	$6,408	$3,408
$150,000	$21,194	$9,180	$12,014	$9,014
$250,000	$29,573	$15,300	$14,273	$11,273
$400,000	$33,591	$24,480	$9,111	$6,111

Note the $400,000 row — savings shrink because reasonable comp ($160,000) is closer to the $184,500 SS wage base, so a larger share of W-2 sits in the Social Security band. Actual reasonable-comp percentages vary materially by industry and role.

Frequently asked questions

What is a sole proprietorship?

A sole proprietorship is an unincorporated business owned by one individual. There is no separate entity for tax purposes — profit is reported directly on Schedule C of your personal Form 1040, and you pay 15.3% self-employment tax on net SE earnings up to the Social Security wage base ($184,500 for 2026) plus 2.9% Medicare above that.

Why would a sole prop elect S-Corp?

The single biggest reason is to reduce SE/FICA tax. A sole prop pays 15.3% on every dollar of profit (up to the SS wage base). An S-Corp owner pays FICA only on the W-2 reasonable-compensation portion; the remaining profit flows through as distributions, free of SE/FICA tax. On $100k of profit, that typically saves $7,000–$10,000 a year.

Do I need to form an LLC first?

Technically you can elect S-Corp on a sole proprietorship using Form 2553 + Form 8832, but in practice almost everyone forms an LLC (or files Articles of Incorporation) first because the S-Corp election requires a corporate-style entity for liability protection and state-level recognition. Forming an LLC is typically $50–$300 plus annual filing fees varying by state.

What annual overhead does S-Corp add?

Typical annual costs: payroll-processing service like Gusto or ADP ($600–$1,500), Form 1120-S tax preparation ($800–$2,500 vs $300–$600 for Schedule C), state minimum tax ($800 in California, varies elsewhere), and quarterly Form 941 / annual W-2 / Form 940 unemployment filings. Net overhead increment over sole prop: roughly $1,500–$3,500 per year for a single-owner business.

What is reasonable compensation?

The IRS requires S-Corp owner-employees to pay themselves a salary equal to the fair market value of services performed. There is no statutory formula — case law uses comparable salaries from BLS OEWS data, time spent, training, and industry norms. The IRS audits S-Corps that pay implausibly low salaries (e.g., $20k W-2 on $200k profit) and reclassifies distributions as wages with payroll tax, interest, and penalties.

What's the break-even point?

Under the assumptions in the table below ($3,000 of added overhead and reasonable compensation of 40% of profit), the S-Corp election starts to pay at roughly $40,000 of annual net profit. Below that the added overhead exceeds the FICA savings, and with different overhead or a different salary the break-even moves. In the table, net savings reach about $1,000 at $50,000 of profit and about $10,000 at $250,000, then shrink as the Social Security wage base is reached (FICA above the base is only the 2.9% Medicare portion).

How does the QBI deduction (Section 199A) interact?

Both sole prop and S-Corp owners can claim the Section 199A QBI deduction — 20% of qualified business income subject to phase-outs starting at $201,750 single / $403,500 MFJ (2026, per Rev. Proc. 2025-32). For an S-Corp, only the distribution portion counts as QBI; W-2 wages paid to yourself do not. For specified-service businesses (SSTBs — health, law, accounting, consulting) above the upper phase-out ($276,750 single / $553,500 MFJ), the QBI deduction zeroes out, removing one of sole prop's offsetting advantages.

Can a sole prop maximize retirement contributions?

A sole prop can fund a Solo 401(k) with employee deferrals up to $24,500 (2026) plus 20% of net SE earnings as an employer contribution, capped at the $72,000 §415(c) limit. An S-Corp owner can only base the 25% employer match on W-2 wages, not on distributions — so a low-salary S-Corp owner has reduced retirement-plan capacity. Sole prop tends to win on raw retirement-plan space.

Try the relevant calculators

Self-Employment Tax Calculator — see the full 15.3% on Schedule C profit
Section 199A QBI Calculator — model the 20% deduction with phase-outs
SEP IRA vs Solo 401(k) — retirement-plan capacity
S-Corp vs LLC — entity vs election distinction
Quarterly Estimated Tax — Form 1040-ES safe harbor
1099 Tax Calculator — independent contractor full-burden
W-2 vs 1099 — employee vs contractor pay

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