How QBI works with an S-Corp
The Section 199A Qualified Business Income deduction lets eligible business owners deduct up to 20% of their qualified business income from their taxable income. For S-Corp owners, QBI is calculated on the K-1 income (your share of the S-Corp profit after your salary is paid), not on your W-2 wages from the S-Corp.
This means your W-2 salary does not qualify for the QBI deduction. Only the pass-through income on your K-1 does. At first glance, this seems like the S-Corp election hurts your QBI deduction. But the math still works heavily in your favor because the SE tax savings far exceed the lost QBI benefit.
A worked example at $150,000
As a sole proprietor with $150,000 net profit: Your QBI deduction is 20% of $150,000 = $30,000 deduction. At a 24% marginal rate, that saves you $7,200 in income tax. But you also pay $21,194 in SE tax. Net tax burden is high.
As an S-Corp with $75,000 salary and $75,000 K-1 income: Your QBI deduction is 20% of $75,000 = $15,000 deduction. At 24%, that saves you $3,600 in income tax. You lost $3,600 in QBI benefit compared to sole prop. But your FICA dropped from $21,194 to $11,475, saving you $9,719. Net gain from S-Corp: $9,719 minus $3,600 = $6,119 better off.
The S-Corp election reduces your QBI deduction but eliminates far more in SE tax. The net result is still thousands of dollars in your favor at any income level above $60,000.
What if you are a Specified Service Trade or Business?
If your business is an SSTB (law, accounting, health, consulting, financial services, athletics, performing arts), the QBI deduction phases out entirely above $243,125 single or $486,250 married filing jointly (2026 thresholds). Above those thresholds, you get zero QBI deduction regardless of your entity structure.
For SSTB owners above the threshold, the S-Corp election is even more valuable because you are not giving up any QBI deduction (you already lost it) and you still get the full SE tax savings. The S-Corp becomes the only meaningful tax reduction tool available.
The bottom line
The S-Corp election does reduce your QBI deduction. But the SE tax savings are 2x to 3x larger than the lost QBI benefit at every income level we have modeled. The calculator on our homepage accounts for this interaction automatically. Run your numbers and see the net result.
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