The QBI Deduction for a Side Business: What Actually Qualifies

The Qualified Business Income deduction is one of the most valuable tax breaks available to anyone with a side hustle, and one of the least understood. Bogleheads.org has a recurring pattern of threads from people with a few thousand dollars of 1099 income asking versions of the same two questions: do I actually qualify for this, and did I calculate it right. Both questions are reasonable, because the deduction interacts with your total income, not just your side business income, in a way that isn't obvious from the name.

There's also a piece of tax legislation from 2025 that changed the calculus meaningfully: this deduction was originally set to expire after 2025, and it didn't. Here's what's actually true for the 2026 tax year.

It's permanent now, not temporary

The QBI deduction, created under Section 199A of the tax code back in 2018, was written into law with a built-in expiration date of December 31, 2025. For years, that sunset date sat in the background of every article about the deduction as a caveat: this might go away.

It didn't. The One Big Beautiful Bill Act, signed into law on July 4, 2025, removed that expiration date from the statute entirely, making the 20% deduction permanent starting with tax years beginning after December 31, 2025, meaning it applies fully for the 2026 tax year and every year after, with no scheduled end date. The same legislation also widened the income range over which certain limitations phase in, which matters more the higher your income runs (more on that below).

The basic mechanics

If you have income from a sole proprietorship, a partnership, an S-corp, an LLC taxed as one of those, or straightforward 1099 self-employment income, you may be able to deduct up to 20% of that qualified business income on your personal tax return. It's a deduction taken below the line, meaning it applies whether or not you itemize, functioning more like the standard deduction than like a Schedule A write-off.

For a taxpayer under the income threshold (covered next), the calculation is simple: the deduction equals the lesser of 20% of your qualified business income, or 20% of your taxable income minus net capital gains. In practice, for most people with modest side income and a normal W-2 salary, the 20%-of-QBI figure is the smaller number, so that's what determines the deduction.

There's also a new minimum floor from the same 2025 legislation: any taxpayer with at least $1,000 of qualified business income from an active trade or business they materially participate in gets a minimum deduction of $400, even if 20% of their actual QBI would calculate to less than that. Both the $1,000 and $400 figures are scheduled to begin adjusting for inflation, in $5 increments, starting after 2026.

The thresholds that actually matter

Above a certain income level, the deduction starts getting limited, and eventually eliminated entirely for some types of businesses. The limitation is based on your total taxable income, not just your business income, which is the detail that trips people up.

For the 2026 tax year, per the IRS's Revenue Procedure 2025-32 inflation adjustments:

Those bands, $75,000 for single filers and $150,000 for joint filers, are wider than they were before 2026. The original law used a $50,000 band for single filers and $100,000 for joint filers; the 2025 legislation widened both, giving more people a gradual phase-out instead of a sharper cutoff.

Below the lower number in each row, you get the full 20% deduction with no limitations, regardless of what kind of business you run. Between the two numbers, limitations phase in gradually. Above the higher number, the limitations apply in full.

The two things that change above the threshold

Once your total taxable income clears the lower threshold, two different limitations start to matter, and which one applies depends on what kind of business you have.

If your side business is a specified service trade or business (SSTB), the deduction phases out entirely as your income moves through the band, reaching zero once you're above the fully-phased-in number. The SSTB category covers health, law, accounting, actuarial science, performing arts, consulting, athletics, financial services, brokerage services, and investing or trading in securities and commodities, plus a catch-all for any business where the main asset is the reputation or skill of its owner or employees. Notably, engineering and architecture are specifically carved out of the SSTB definition, so those two professions keep the deduction even at high income, unlike most other consulting-adjacent fields.

If your side business isn't an SSTB, the deduction doesn't disappear above the threshold, but it becomes limited by a calculation tied to how much the business pays in W-2 wages and how much depreciable property it owns. A small side business with no employees and no significant equipment, freelance writing, consulting work structured to avoid the SSTB label, a small e-commerce shop, will often see this limitation bite hard once income is high enough, simply because there's no wage base or property basis for the calculation to work from. This is a genuinely complicated part of the code; if your total income is anywhere near the thresholds above and your side business generates real money, it's worth a conversation with a CPA rather than estimating it yourself.

Why your W-2 salary matters even though it isn't QBI

Your W-2 wages themselves never count as qualified business income; only self-employment, partnership, S-corp, and similar pass-through income does. But your W-2 wages absolutely count toward the total taxable income figure that determines where you land on the threshold table above.

This is the part that catches people with a well-paying job and a small side hustle off guard. A software engineer earning $220,000 in W-2 wages with a modest $8,000 consulting side gig isn't evaluated against a $8,000 income threshold. They're evaluated against their full taxable income, likely somewhere north of $200,000 once you add the side income and subtract deductions, which for a single filer in 2026 puts them right around the phase-in threshold ($201,750) even though the side business itself is small. If that consulting work counts as an SSTB, this person could be losing a meaningful chunk of the deduction on a business that, viewed in isolation, looks nowhere near "high income."

A worked example

Take a married couple filing jointly. One spouse earns $175,000 in W-2 wages; the other runs a freelance graphic design business (not an SSTB) that nets $35,000 after business expenses. Combined taxable income, after standard deduction and other adjustments, comes to roughly $195,000, well under the $403,500 threshold for joint filers.

Since they're under the threshold, the SSTB question and the wage/property limitation don't apply at all. The deduction is simply the lesser of 20% of the $35,000 QBI ($7,000) or 20% of their taxable income minus net capital gains (roughly $39,000, comfortably larger). The smaller number wins: a $7,000 deduction, worth about $1,540 in federal tax savings at a 22% marginal rate.

Now change one detail: say the freelance work is management consulting instead of graphic design, an SSTB category, and the couple's combined taxable income is $580,000 instead of $195,000, above the $553,500 fully-phased-in threshold for joint filers. In that scenario, the SSTB deduction phases all the way to zero. Same 20%-of-QBI math on paper, but no deduction at all, because of what kind of business it is and how much the couple earns from everything combined.

What the deduction doesn't touch

QBI deduction only reduces income tax. It has no effect on self-employment tax, meaning you still owe the full Social Security and Medicare tax on your net self-employment earnings regardless of how large your QBI deduction turns out to be. It's easy to conflate the two since they're both calculated off the same underlying business income, but they run on entirely separate tracks.

What to actually do with this

If you have side income and you're anywhere near the thresholds above, don't estimate this deduction with a rule of thumb; the SSTB question and the wage/property limitation are genuinely complicated, and getting them wrong in either direction either costs you a deduction you were entitled to or creates an underpayment problem. A CPA who does small-business or self-employment returns regularly can run the actual numbers in under an hour for most straightforward side businesses.

Regardless of how the deduction lands, the business itself is worth tracking as part of your overall financial picture, not just at tax time. If you're building equity in the side business itself, not just earning income from it, our guide to tracking side business equity covers how to value it, and the tax map of your net worth walks through how different account types and income sources interact with your overall tax picture. If the business is growing enough that you're thinking about liability protection or a different entity structure, entity structuring for wealth protection is the next place to look. In Steady Wealth, your side business shows up as its own asset alongside everything else, so you can see it as part of your total position, not a separate ledger you have to check on its own.

Frequently asked questions

Is the QBI deduction still available for 2026?

Yes. Section 199A was originally scheduled to expire after 2025, but the One Big Beautiful Bill Act, signed in July 2025, made the deduction permanent with no expiration date, effective for tax years beginning after December 31, 2025.

Does my side hustle qualify for the QBI deduction?

Most sole proprietorships, single-member LLCs, partnerships, and S-corps with real business income qualify, as does straightforward 1099 self-employment income. Whether you get the full 20% depends on your total taxable income relative to the current thresholds, and, above those thresholds, on whether your business falls into the specified service trade or business (SSTB) category.

Does the QBI deduction reduce my self-employment tax?

No. It only reduces federal income tax. Self-employment tax, the Social Security and Medicare tax on your net self-employment earnings, is calculated separately and isn't affected by the QBI deduction at all.

Do I need to itemize deductions to claim QBI?

No. It's a below-the-line deduction available whether you take the standard deduction or itemize, calculated on Form 8995 or Form 8995-A depending on your income and business type.

How is QBI calculated if I have both a W-2 job and a side business?

Your W-2 wages themselves don't count as qualified business income, but they do count toward the total taxable income figure that determines whether you're under, within, or above the phase-out thresholds. A high W-2 salary can push you into the limited range even if your side business income by itself is modest.