Solo Founder Tax Planning

The U.S. tax structure for solo founders treats the same dollar of business income very differently depending on how the business is organized. A founder netting $120,000 as a default LLC pays a structurally different tax bill than the same founder, with the same revenue and expenses, electing S-corp status. The gap is large enough to matter and small enough to be wiped out by the wrong decision at the wrong income level.

This piece covers what SE tax is, how the S-corp election changes the math, where the break-even actually sits on 2026 federal numbers, and the second-order effects (state tax, payroll cost, the QBI deduction) that move it for individual founders. It is not tax advice. The IRS publications cited^[1][3] and a CPA who has run the math on your specific state are the authoritative sources.

What self-employment tax actually is

Self-employment tax is the combined Social Security and Medicare contribution that W-2 employees split with their employer. The W-2 employee pays 7.65% (6.2% Social Security + 1.45% Medicare) and the employer pays a matching 7.65%. A self-employed person pays both halves, which is the 15.3% rate.

The 2026 mechanics:

• The tax base is 92.35% of net business income. That factor removes the equivalent of the employer's half, so the effective rate on net business income is 14.13% (15.3% × 0.9235)^[1].
• Social Security portion: 12.4% on that base up to the 2026 wage base of $184,500 ($176,100 in 2025)^[6].
• Medicare portion: 2.9% on all of it, no cap.
• Additional Medicare: 0.9% on earnings above $200,000 single filer / $250,000 joint.
• Half of the SE tax is deductible above the line on Form 1040, which lowers income tax, not the SE tax itself.

SE tax sits separately from federal and state income tax. A founder at $100,000 net Schedule C income pays $14,130 of SE tax ($100,000 × 0.9235 × 0.153), then pays federal income tax on what is left after the half-SE deduction, the standard deduction and the QBI deduction, then state income tax. SE tax is the line that surprises first-time solo founders coming from W-2 employment, where the employer-paid half is invisible.

Default LLC: SE tax on every dollar

A single-member LLC with no tax election is a "disregarded entity" for federal purposes. All net income flows to the founder's Schedule C and the entire net is subject to SE tax. There is no salary distinction, no distributions, just one line of net business income.

For a founder at $80,000 net income, the math:

SE tax = $80,000 × 0.9235 × 0.153 = $11,304

(The 0.9235 multiplier converts net business income to "net earnings from self-employment," which is the actual SE-tax base. It roughly equates the self-employed taxpayer with a W-2 employee whose wages already exclude the employer-side FICA.)

Half of that ($5,652) is deductible above the line for income tax purposes, which saves about $680 at the 12% federal bracket or about $1,240 at 22%. The net SE-tax cost is therefore about $10,060 to $10,630 on $80,000 of business income, or 12.6% to 13.3%.

Default LLC has three real advantages: zero compliance cost beyond the personal return, no payroll system, no separate corporate tax filing. For founders at low net income, those advantages outweigh the SE-tax inefficiency.

The S-corp election and reasonable salary

The S-corp election (Form 2553) reclassifies an LLC or corporation for tax purposes. Income flows through to the owner's personal return (similar to default LLC), but the structure introduces a salary/distribution split:

• Reasonable salary: the portion the owner pays themselves as a W-2 wage, subject to full payroll taxes (FICA, FUTA, state unemployment).
• Distributions: additional profit drawn from the business, subject to ordinary income tax but NOT to SE tax / FICA.

The IRS rule is that the salary must be reasonable compensation for the services the owner provides, judged on factors such as training, duties, time spent and what comparable businesses pay for similar services^[3]. A solo founder running a software business cannot pay themselves $20,000 salary and take $200,000 in distributions; the IRS has reclassified low-salary cases for decades. There is no IRS safe harbor percentage. Many advisers start from 40% to 60% of profit as a rule of thumb, but the defensible number comes from comparable wages for the work you actually do, for example BLS occupational wage data for the role^[5].

Worked illustration. A solo SaaS founder with $200,000 net business income pays $90,000 reasonable salary and takes $110,000 in distributions. Payroll-tax outcome:

• Salary FICA: $90,000 × 0.153 = $13,770 (split nominally between owner and corporation, but the owner bears both as the only shareholder).
• Distribution FICA: $0 on $110,000.
• Compare to default LLC: $200,000 × 0.9235 = $184,700 of net earnings, $200 above the 2026 wage base, so SE tax is $184,500 × 12.4% + $184,700 × 2.9% = $28,234.

Payroll-tax savings on this scenario: about $14,500 a year, before the cost of S-corp compliance and before the income-tax effects covered in the worked example below.

Where the break-even sits (and why it moves)

The crossover where S-corp savings start to exceed S-corp overhead depends on three founder-specific numbers:

• Net business income. The higher, the more SE tax savings the S-corp generates per dollar of distribution.
• Reasonable salary ratio. The lower the defensible salary for your role, the larger the distribution and the saving; a founder doing work that commands a senior-engineer wage faces a higher salary and a smaller saving.
• S-corp overhead. A payroll service (Gusto lists $49 a month plus $6 per person on Simple and $80 plus $12 on Plus, so $660 to $1,104 a year for a one-person payroll^[10]), a paid preparer for the S-corp return, and state-level S-corp taxes and fees (Massachusetts: a $456 minimum excise^[11]; California: 1.5% of net income with an $800 minimum^[9]; New York: a fixed-dollar minimum from $25 at receipts up to $100,000^[12]). Preparer fees are quoted per engagement and no current survey publishes them, so the tables below assume $2,500 of overhead a year (payroll taxes only) and $4,000 (with income tax); put your own quotes in their place.

Payroll taxes alone, 2026 rates, 50% salary ratio, $2,500 overhead:

Net biz income   Default LLC SE   S-corp FICA   Saving    Net of overhead
  $50,000          $7,065           $3,825        $3,240    $740
  $70,000          $9,891           $5,355        $4,536    $2,036
  $80,000          $11,304          $6,120        $5,184    $2,684
  $100,000         $14,130          $7,650        $6,480    $3,980
  $150,000         $21,194          $11,475       $9,719    $7,219
  $200,000         $28,234 (SS cap) $15,300       $12,934   $10,434

On payroll taxes alone, the saving covers $2,500 of overhead from about $38,600 of profit. That understates the real break-even, because the S-corp salary is not qualified business income: the election shrinks the 20% QBI deduction^[2] and so raises income tax. With income tax and $4,000 of overhead included, the worked example below puts the crossover at about $66,000.

Why the threshold is not fixed: every extra $1,000 of overhead moves the payroll-only break-even up by about $15,000, so a founder paying a CPA $5,000 instead of $1,500 needs far more profit before the election pays. In California, S corps pay 1.5% of net income with an $800 minimum^[9], while an LLC already pays an $800 annual tax, so the election adds 1.5% of the S corp's net income above about $53,000 (where 1.5% passes $800): a cost to include, but rarely the deciding one. States without a personal income tax, such as Texas and Florida, leave the federal comparison close to the whole story.

Run your own numbers with the Profit Margin Calculator to identify net business income before tax planning. The margin calculation is the input to the SE-tax calculation; both have to be defensible before the S-corp decision is sound.

Worked example at three income levels

Same founder, same business (US-based solo SaaS, single-member entity), three income levels, comparing default LLC and S-corp election on 2026 federal rules: single filer, $16,100 standard deduction and 2026 brackets^[7], the 20% QBI deduction^[2], no state income tax (as in Texas or Florida), $1,800 payroll service and $2,200 CPA cost for the S-corp return. The S corp's share of FICA, federal unemployment tax ($42) and the overhead are business expenses; the owner's salary is not QBI.

SCENARIO A: $60,000 net business income (year 1)
  Default LLC:
    SE tax                                    $8,478
    Federal income tax                        $3,559
    Total federal                             $12,037

  S-corp election:
    Salary $30,000, distribution of the rest
    FICA (both halves) + FUTA                 $4,632
    Federal income tax                        $3,692
    Payroll + CPA overhead                    $4,000
    Total federal + overhead                  $12,324

  Verdict: default LLC wins by $286. S-corp not yet worth it.

SCENARIO B: $100,000 net business income (year 2)
  Default LLC:
    SE tax                                    $14,130
    Federal income tax                        $8,235
    Total federal                             $22,365

  S-corp election:
    Salary $50,000, distribution of the rest
    FICA (both halves) + FUTA                 $7,692
    Federal income tax                        $9,585
    Payroll + CPA overhead                    $4,000
    Total federal + overhead                  $21,277

  Verdict: S-corp wins by $1,087.

SCENARIO C: $200,000 net business income (year 3)
  Default LLC:
    SE tax (Social Security capped)           $28,234
    Federal income tax                        $25,196
    Total federal                             $53,431

  S-corp election:
    Salary $90,000, distribution of the rest
    FICA (both halves) + FUTA                 $13,812
    Federal income tax                        $29,356
    Payroll + CPA overhead                    $4,000
    Total federal + overhead                  $47,168

  Verdict: S-corp wins by $6,263.

At low profit the default LLC wins on cost and simplicity. On these assumptions the S-corp pulls ahead in the mid-$60,000s, and its advantage grows with profit. Income tax is higher under the S-corp in every scenario, because the salary is excluded from QBI; the payroll-tax saving has to outrun that and the overhead.

S-corp costs: payroll, accounting, complexity

The financial overhead is only part of what the election adds:

• Payroll service. Gusto, ADP RUN, Square Payroll, or equivalent; Gusto's Simple plan is $55 a month for a one-person payroll ($49 plus $6 per person)^[10]. The service handles federal and state withholding deposits, quarterly 941s, annual W-2, and the state unemployment registrations that vary by state.
• S-corp tax return (Form 1120-S). The S corporation files its own return and issues a Schedule K-1 that flows to your personal return^[4]; most founders pay a preparer for it, at a fee quoted per engagement. DIY is technically possible, but the return interacts with payroll filings and state forms in ways that are easy to get wrong.
• Reasonable compensation documentation. The IRS expects a defensible justification for the salary. Most CPAs document comparable wages for the role (BLS occupational wage data is a common starting point^[5]) in a memo to file. It is a short exercise the first year and should be revisited annually.
• State complexity. California's 1.5% S-corp tax, Tennessee's franchise and excise tax, New York City's general corporation tax, Illinois's replacement tax. Each adds a layer that the federal-only break-even table misses. A founder in a high-tax state should run state-specific numbers before electing.
• Cash-flow timing. Payroll runs require cash in the operating account on payroll dates, which is a different cash-management pattern than the lumpy quarterly estimated tax payments of default LLC.

Edge cases and second-order effects

• Solo 401(k) contribution math changes. Default LLC: contribution base is net SE income minus half of SE tax. S-corp: contribution base is W-2 salary. A founder paying a low salary to maximize FICA savings reduces their own retirement-contribution ceiling. The optimal salary often lands above the FICA-minimization point because of the 401(k) base.
• QBI deduction interaction. Section 199A allows a deduction of up to 20% of qualified business income for pass-through entities, including S-corps and default LLCs, and continues for tax years after 2025^[2]. Wages and S-corp reasonable compensation are not QBI, so every dollar of salary shrinks the deduction; the worked example shows the effect. The deduction also phases out at higher incomes for "specified service trades and businesses" (most consulting). Optimal salary is a joint optimization of FICA savings and QBI preservation.
• Health insurance. S-corp shareholder health insurance must be added to W-2 wages for the 2% owner, which sounds like a tax hit but recovers on the personal return as a self-employed health insurance deduction. Net is usually neutral, but the paperwork is non-trivial.
• State residency changes mid-year. A founder relocating from California to Texas mid-year creates a multi-state S-corp filing situation that can cost more in CPA fees than the relocation saves in the first year. Plan around it rather than discovering it at filing time.
• Reasonable comp scrutiny. Low salaries next to large distributions are what invite IRS reclassification. Set the salary from comparable wages for the role, not from a target percentage, and keep the evidence.

Common founder tax mistakes

• Electing S-corp too early. A first-year founder netting $30,000 who elects S-corp with a 50% salary saves about $1,900 in payroll taxes and pays $2,500 to $4,000 in overhead, before the smaller QBI deduction. The election is due within 2 months and 15 days of the start of the tax year it applies to, with relief available for late elections^[8]; it can be revoked later, but a year on the wrong structure is not recoverable.
• Setting salary too low. The temptation is to minimize FICA by paying $10,000 salary and taking $90,000 distribution. If the IRS reclassifies distributions as wages, the payroll taxes come back with penalties and interest.
• Forgetting state-level S-corp taxes. California's 1.5% applies to the S corp's net income with an $800 minimum; LLCs there already pay $800, so the incremental cost is modest but real. Always run the state column.
• Not separating personal and business expenses cleanly. Both default LLC and S-corp require the founder to maintain a clean business-expense trail. Schedule C audit defense and S-corp audit defense both depend on the same fundamentals: receipts, mileage logs, business-purpose documentation.
• DIY S-corp returns. Form 1120-S has more lines and more interaction with payroll and state forms than founders typically expect. Getting it prepared properly once costs less than amending it later.
• Skipping the quarterly estimated tax payments. Both structures require quarterly estimates. The underpayment penalty works like interest at the rate the IRS sets each quarter. The fix is one calendar reminder.

The S-corp decision is not a permanent commitment. Founders revoke and re-elect as income changes, business structure shifts, or state residency changes. The honest math is the same every year: net business income, a reasonable salary set from comparable wages, overhead in your specific state and CPA tier, the QBI effect, run the table, decide. On 2026 federal numbers with typical overhead, the break-even for a solo founder sits in the mid-$60,000s of profit; state taxes, a higher salary or higher fees push it up, and that is the income level at which the conversation with a CPA stops being optional.