The 20% small business deduction has been on the books since 2018, and it’s one of the most valuable tax breaks available to local business owners — worth, for many, tens of thousands of dollars a year in reduced federal income tax. NFIB has been actively promoting it following its passage and is offering members a calculator to estimate their savings, which signals something important: even after years, awareness and uptake remain lower than they should be.
If you run a sole proprietorship, LLC, S-corp, or partnership, this deduction may apply to your business income. The reason so many owners miss it or misclaim it isn’t complexity for its own sake — it’s that the deduction comes with income thresholds, phase-outs, and W-2 wage tests that interact in ways that aren’t obvious from reading a tax prep checklist.
What the Deduction Is
The Section 199A deduction — often called the QBI deduction, for Qualified Business Income — allows eligible pass-through business owners to deduct up to 20% of their qualified business income from their federal taxable income. Since pass-through income is taxed at individual rates rather than the corporate rate, this deduction functions as a way to bring effective pass-through tax rates closer to the corporate rate.
For example: if your pass-through business generates $200,000 in qualified business income, you may be able to deduct $40,000 from your taxable income before applying your individual rate. At a 24% marginal rate, that’s $9,600 in tax savings. At a 32% rate, it’s $12,800.
The IRS has a detailed overview of Section 199A qualified business income, and your tax preparer should be running this calculation for every eligible return they prepare — but it helps to understand the basic structure yourself.
Who Qualifies
The deduction applies to income from:
- Sole proprietorships (Schedule C income)
- S-corporations (your share of S-corp income)
- Partnerships and LLCs taxed as partnerships
- Real estate investment trusts (REITs) and certain publicly traded partnerships
What doesn’t qualify: wages and salary you earn as a W-2 employee (even of your own S-corp), capital gains, dividends, and interest income. If your business makes money, the pass-through income from that business is generally what’s eligible.
The Income Thresholds That Change the Math
Here’s where it gets complicated. At lower income levels, the deduction is straightforward: 20% of qualified business income, full stop. But once your total taxable income crosses certain thresholds, the rules change significantly.
For 2026, the phase-in begins at approximately $197,300 for single filers and $394,600 for married filing jointly (these limits adjust annually for inflation — verify current figures with the IRS or your accountant). Above those thresholds, two limitations kick in:
1. The W-2 wage limitation. The deduction gets capped at 50% of the W-2 wages your business paid to employees, or 25% of W-2 wages plus 2.5% of the unadjusted basis of qualified property — whichever is greater. This is why a solo operator or single-member LLC with no employees may see a reduced deduction above the threshold, while a business with a significant payroll may not be affected.
2. Specified service trade or business (SSTB) phase-out. Certain professional service businesses — consultants, lawyers, doctors, financial advisors, accountants — are classified as SSTBs and face an additional phase-out above the income thresholds. At incomes well above the threshold, the SSTB deduction phases out entirely. If you’re in a professional service field, this distinction matters a great deal.
Common Ways Owners Misclaim It
Claiming it when the W-2 limit cuts it to zero. A high-income owner of a single-member LLC with no employees above the income threshold may have a QBI deduction that’s limited to near zero by the W-2 wage test. Running the calculation wrong means overclaiming.
Missing it entirely for S-corp shareholders. If you’re an S-corp shareholder and you’re paying yourself a reasonable salary (as required), your W-2 wages from the S-corp are not eligible for the QBI deduction — but the remaining business income distributed to you as a shareholder generally is. These two buckets need to stay separate.
Mixing in non-qualified income. Capital gains from selling business property, interest income, and certain other items need to be excluded from the QBI calculation. Mixing them in inflates the deduction.
Not aggregating multiple businesses. If you own more than one pass-through business, you may be able to elect to aggregate them for QBI purposes — which can increase your W-2 wage base and improve your deduction. This aggregation election has to be made consistently once taken.
What to Bring to Your Accountant
If you haven’t specifically discussed QBI with your tax preparer — or if you’re changing accountants — bring the following to the conversation:
- All pass-through K-1s and Schedule C income for the year
- W-2 wage totals paid by each business you own (not wages paid to you — wages paid to others)
- Documentation of the unadjusted basis of depreciable property used in the business (useful for the alternative wage/asset limitation)
- A list of every business entity you have an ownership stake in, including passive investments
If your preparer hasn’t been calculating the QBI deduction on your returns and you were eligible, you may be able to amend prior-year returns to claim what you missed. The standard three-year lookback period for amended returns applies.
The NFIB’s personalized calculator can give you a quick ballpark estimate. For anything beyond that estimate, a CPA or enrolled agent familiar with Section 199A is the right call — the penalty for overclaiming a QBI deduction is the same as for any other overstated deduction, and the wage-limit calculations benefit from professional review.
If you’ve been filing your business taxes without specifically discussing this deduction, it’s worth a conversation before your next return is due.
