How Your S Corporation Salary Sets Payroll Tax, Your 401(k) and the QBI Deduction

Key takeaways

The salary is one number with three consequences: payroll tax, the solo 401(k) ceiling and, above the income thresholds, the wage limit on the section 199A deduction.
In 2026 an owner-only solo 401(k) is full at about $190,000 of salary, because the $24,500 deferral plus 25% profit sharing reach the $72,000 annual limit; more salary buys no more retirement room.
Above the thresholds, too small a salary throttles the 199A deduction and too large a salary shrinks the income being deducted; the deduction peaks where the two limits cross.
The lowest-tax column in a model is not a recommendation. Reasonable compensation is a facts and circumstances question, and a compensation study decides which salaries are defensible.

If you own an S corporation, you choose how much of the profit to pay yourself as salary and how much to take as a distribution. Most of the advice stops at payroll tax: salary carries it and distributions do not, so pay yourself as little as you can defend. That leaves out two things the same number controls. The salary sets how much you can put into a solo 401(k), and above the income thresholds it caps the qualified business income deduction under section 199A. Change the salary and all three move at once.

The model below runs four salary levels for one fictional owner with $900,000 of profit. Choose a salary to follow it down the table.

The model

Paying yourself out of an S corporation

Illustrative. A fictional owner, not a projection of results for any client.

Paying yourself out of an S corporation: four salary levels for a fictional owner with $900,000 of profit. The $270,000 column has the lowest total federal tax of the four.
Salary level	$120,000	$190,000	$270,000	$360,000
Net business profit before owner compensation	$900,000	$900,000	$900,000	$900,000
Salary on a W-2	$120,000	$190,000	$270,000	$360,000
Salary as a share of profit	13.3%	21.1%	30.0%	40.0%
Owner draw, taken as a distribution	$780,000	$710,000	$630,000	$540,000
Payroll tax
Employer share	$9,180	$14,194	$15,354	$16,659
Employee share	$9,180	$14,194	$15,534	$17,649
Total payroll tax	$18,360	$28,388	$30,888	$34,308
Solo 401(k), the ceiling is keyed to the salary
Elective deferral	$24,500	$24,500	$24,500	$24,500
Employer profit sharing, 25% of salary	$30,000	$47,500	$47,500	$47,500
After-tax contribution, the mega backdoor	$17,500	none	none	none
Total annual additions, IRC 415(c)	$72,000	$72,000	$72,000	$72,000
Cash the salary must cover, deferral plus after-tax	$42,000	$24,500	$24,500	$24,500
Qualified business income, also keyed to the salary
K-1 ordinary business income	$740,820	$648,306	$567,146	$475,841
20% of qualified business income	$148,164	$129,661	$113,429	$95,168
50% of W-2 wages, the limitation	$60,000	$95,000	$135,000	$180,000
Taxable income before the deduction	$804,120	$781,606	$780,446	$779,141
Section 199A deduction allowed	$60,000	$95,000	$113,429	$95,168
Which limit binds	50% of wages	50% of wages	20% of QBI	20% of QBI
What it costs
Taxable income	$744,120	$686,606	$667,017	$683,973
Federal income tax	$197,981	$177,851	$170,994	$176,929
Total federal tax	$216,341	$206,239	$201,882	$211,237
Effective federal rate on the profit	24.0%	22.9%	22.4%	23.5%

Tinted column: the lowest total federal tax of the four salary levels.

Assumed: married filing jointly, Florida, not a specified service trade or business, no qualified property, owner under 50, and 2026 federal law. Illustrative, and not a projection of results for any client.

What the salary is actually doing

It sets the payroll tax

Every dollar of salary below the Social Security wage base, $184,500 in 2026, carries 12.4% of Social Security and 2.9% of Medicare across the employer and employee shares. Above the wage base only Medicare applies, and the additional 0.9% Medicare tax starts once a married couple's wages pass $250,000. A dollar taken as a distribution carries none of it. In the model, moving from the lowest salary to the highest adds about $16,000 of payroll tax.

It sets the retirement plan ceiling

In a solo 401(k), the business can contribute up to 25% of salary as profit sharing, on top of your own $24,500 deferral, and the total for the year cannot exceed $72,000 or 100% of pay. At a $120,000 salary, the deferral and profit sharing come to $54,500, and an after-tax contribution fills the remaining $17,500 of room.

That after-tax bucket, converted to Roth inside the plan, is what makes a lower salary workable, the mega backdoor Roth. With no employees in the plan, the nondiscrimination test that normally limits after-tax contributions is not a constraint. The catch is cash: the deferral and the after-tax contribution both come out of your paycheck, $42,000 of a $120,000 salary in the model.

From about $190,000 of salary, the deferral plus 25% profit sharing reach the $72,000 limit on their own. Past that point, more salary buys no more retirement funding at all.

It sets the section 199A deduction

Qualified business income is the K-1 income left after the salary. For a married couple in 2026, once taxable income passes $553,500 (the $403,500 threshold plus a $150,000 phase-in range), the deduction for a business that is not a specified service business is capped at the greater of 50% of W-2 wages or 25% of wages plus 2.5% of qualified property. This owner has no qualified property, so the cap is half the salary.

Too small a salary throttles the deduction: at $120,000 of salary it is limited to $60,000. But every dollar of salary also comes out of qualified business income, so too large a salary shrinks the thing being deducted. The deduction peaks where 20% of qualified business income crosses 50% of wages, and the Which limit binds row shows which side of that crossing each column sits on.

Putting it together

The tinted column, a $270,000 salary, carries the lowest total federal tax of the four. Of the four levels in the model, it sits closest to where the 199A deduction peaks, and it already fills the 401(k). That is a result of this owner's numbers, not a rule. A different profit, a state income tax, employees on payroll or a cash balance plan would move it.

The number still has to be reasonable

None of this decides the salary. An S corporation owner who works in the business has to be paid reasonable compensation for those services, and the IRS treats it as a facts and circumstances question: duties, time, and what comparable businesses pay for comparable work (IRS Fact Sheet 2008-25). When pay is too low, the IRS can recharacterize distributions as wages, as the Eighth Circuit upheld in David E. Watson, P.C. v. United States (2012).

A rule of thumb, such as a third of profit, is a place to start a conversation, not a defense. The model tells you what a given salary costs. A compensation study tells you which salaries are available to choose from.

What the model leaves out

Health insurance for a more-than-2% shareholder, which is reported as wages
State and local income tax outside Florida
Employees other than the owner, who change the retirement plan's cost and testing
The qualified property alternative for the 199A wage limit
A defined benefit or cash balance plan, which can sit on top of the 401(k)
Whether your plan document permits after-tax contributions and in-plan Roth conversions; many prototype solo 401(k) documents do not

How we use it

For a business owner, we run this with your actual profit, your state, your plan document and your household's other income, alongside the rest of business owner planning: the retirement plan design and the eventual exit. The salary you settle on, and the study that supports it, then go to your payroll provider and your tax preparer to carry out.

Frequently asked questions

Is a third of profit a safe salary for an S corporation owner?

No rule of thumb is a safe harbor. Reasonable compensation turns on the duties you perform, the time you spend and what comparable businesses pay for comparable work. A third of profit happens to land near the lowest-tax column in this model, but that is a result of this owner's numbers, and a compensation study is what supports the salary you choose.

Does a higher salary always mean a bigger solo 401(k)?

No. With no employees, the $24,500 deferral plus 25% profit sharing reach the $72,000 limit at about $190,000 of salary in 2026. Below that point an after-tax contribution can fill the gap, if the plan document allows it. Above it, more salary adds payroll tax without adding retirement room.

Why doesn't the lowest salary produce the lowest tax?

Above the taxable income thresholds, the section 199A deduction for a business that is not a specified service business is capped at 50% of W-2 wages when there is no qualified property. At a $120,000 salary the model's deduction is held to $60,000, and the income tax that costs is larger than the payroll tax the low salary saves.

Joseph G. Valerio, CFP®, EAFounder and Lead Advisor at Valerio Wealth Management, a fee-only, fiduciary virtual family office in Miami, Florida. One advisor, credentialed in both financial planning and federal tax. About Joseph

This article is general education, not individualized advice, and it is not tax, legal, or accounting advice. Figures reflect federal law for the year stated and can change. Valerio Wealth Management does not prepare or file tax returns. Speak with a qualified professional about your own situation before acting.