Federal Section 199A QBI Deduction Calculator (20% Pass-Through)

How this calculator works

IRC § 199A is the Tax Cuts and Jobs Act's answer to a structural problem: the TCJA cut the C-corporation rate to a flat 21% under IRC § 11, but most American businesses are pass-throughs — sole proprietorships, partnerships, and S-corporations — whose owners pay tax at individual rates that top out at 37%. To keep the pass-through structure competitive, Congress enacted § 199A: a deduction of up to 20% of qualified business income (QBI) for non-corporate owners of qualified trades or businesses.

The deduction is mechanically the most complex provision in the post-TCJA Internal Revenue Code. It has three income zones, a special carve-out for "Specified Service Trades or Businesses" (SSTBs — health, law, accounting, consulting, financial services, investment management), a W-2 wage limit that protects against pure-passive structures, and an alternative wage limit pegged to invested capital. Layer in aggregation, the rental real estate safe harbor under Rev. Proc. 2019-38, and the TCJA sunset clause, and § 199A is the single most-litigated and most-FAQ'd section enacted in the last two decades.

This calculator models the federal-pure § 199A mechanic in a single planning view: the tentative 20%, the overall-limit ceiling, both wage-limit formulas, the phase-in band position, and the actual deduction after all limits, plus a toggle for the post-2025 sunset scenario.

The basic formula

Under IRC § 199A(a), the deduction is the lesser of:

1. 20% of QBI from the qualified trade or business, OR
2. 20% of (taxable income before the QBI deduction − net capital gains).

The second prong is the overall-limit ceiling. It prevents the deduction from creating a refund-generating position when the taxpayer has minimal ordinary-rate income but substantial capital gains (which already enjoy preferential rates). Net capital gains for this purpose include qualified dividends under IRC § 199A(e)(3) read with § 1(h)(11) — both are stripped out of the overall-limit base.

For taxpayers below the income threshold, that's the entire formula: 20% of the smaller of QBI or taxable income less capital gains. The W-2 wage limit, the UBIA limit, and the SSTB cutoff do NOT apply below the threshold. Most small-business owners — the vast majority of Schedule C filers and most small partnerships and S-corps — never see anything more complicated than this.

The three income zones

The complexity kicks in at the income threshold. § 199A defines three zones based on taxable income before the QBI deduction:

1. Below threshold. Full 20% deduction with no W-2 wage limit, no UBIA test, no SSTB cutoff. Just the lesser-of-two formula above.

2. Within the phase-in band. The W-2 wage limit applies proportionally (for non-SSTBs) and the SSTB carve-out applies proportionally (for SSTBs). Both phase in linearly across the band.

3. Above the full phase-in ceiling. The W-2 wage limit applies in full (for non-SSTBs). The SSTB cutoff applies in full — SSTB deduction is $0.

The 2026 thresholds (TCJA-indexed; current-law continuation assumed):

• Single / HoH: phase-in starts at $191,950, fully phased in at $241,950 ($50K band).
• MFJ: phase-in starts at $383,900, fully phased in at $483,900 ($100K band).
• MFS: half of single — $95,975 to $120,975.

The W-2 wage limit (above phase-in)

Above the full phase-in ceiling, a non-SSTB deduction is capped at the greater of two formulas under IRC § 199A(b)(2)(B):

1. 50% of W-2 wages paid by the qualified trade or business, OR
2. 25% of W-2 wages + 2.5% of UBIA of qualified property.

The 25%+2.5% alternative exists to relieve capital-intensive businesses where wages are low relative to invested capital — rental real estate especially, and manufacturing operations with substantial machinery. UBIA (Unadjusted Basis Immediately after Acquisition) is the original cost basis of qualified property held by the business at year-end, not current depreciated basis. Land doesn't count; buildings, equipment, machinery, and furniture do.

The SSTB carve-out

A Specified Service Trade or Business under IRC § 199A(d)(2)(A) is one in:

• Health (physicians, dentists, mental-health providers, but NOT medical-equipment or medical-research operations)
• Law
• Accounting
• Actuarial science
• Performing arts (actors, musicians, athletes-as-performers)
• Consulting
• Athletics
• Financial services (financial planners, retirement advisors)
• Brokerage services (securities/commodities — NOT real estate)
• Investing, investment management, trading
• Dealing in securities
• Reputation-or-skill catch-all: any business whose principal asset is the reputation or skill of one or more employees or owners

Critical exclusions: engineering and architecture are NOT SSTBs (explicit § 199A(d)(2)(A) carve-out). Real-estate brokerage is NOT a brokerage service for § 199A — only securities/commodities brokerage.

SSTB status only matters above the income threshold. Below the threshold, an SSTB owner gets the full 20% deduction just like any other pass-through owner. Within the phase-in band, the QBI itself phases out linearly. Above the full phase-in ceiling, an SSTB owner gets $0 — no exceptions, no W-2 wage workaround, nothing.

Worked example 1 — single sole proprietor, well below threshold

A single sole proprietor (consultant or otherwise) has $80,000 of QBI and $100,000 of taxable income before QBI. Single threshold starts at $191,950, so this is well below the phase-in.

• 20% × QBI: $80,000 × 20% = $16,000
• 20% × (TI − net cap gains): $100,000 × 20% = $20,000
• Deduction: min($16,000, $20,000) = $16,000

The W-2 wage limit, UBIA test, and SSTB cutoff all do not apply. Even though the taxpayer is a consultant (an SSTB above the threshold), the SSTB classification is irrelevant here — below the threshold, all pass-throughs get the full 20%.

Worked example 2 — MFJ non-SSTB still below threshold

An MFJ couple operates a non-SSTB business and reports $300,000 of taxable income before QBI with $200,000 of QBI. MFJ threshold starts at $383,900, so this is still below the phase-in.

• 20% × QBI: $200,000 × 20% = $40,000
• 20% × TI: $300,000 × 20% = $60,000
• Deduction: min($40,000, $60,000) = $40,000

$40K of deduction shelters $40K of taxable income — at the couple's 24% marginal bracket, that's roughly $9,600 of federal tax savings.

Worked example 3 — single SSTB doctor, above the full phase-in ceiling

A single physician has $250,000 of taxable income and $200,000 of QBI from her practice. The single phase-in ceiling is $241,950 — $250,000 is above the ceiling. As an SSTB, she gets:

• Deduction: $0

The SSTB cutoff is absolute above the ceiling. She can't restructure the deduction with a higher W-2 (the SSTB cutoff supersedes the wage limit). The only paths out are: (a) defer income into a future low-income year to drop below the threshold, (b) make a larger pre-tax retirement contribution to lower taxable income below the threshold, or (c) restructure the practice (e.g., spin out a non-SSTB management entity that owns the building and leases to the practice — a planning move that gets aggressive scrutiny from the IRS and requires careful § 1.199A-5(c) anti-abuse analysis).

If the same physician had $200,000 of taxable income (below the $191,950 phase-in start), she would qualify for the full 20% × $200,000 = $40,000 deduction. The cliff between $191,950 and $241,950 is the SSTB phase-out band — at $216,950 (halfway through), her deduction would be 50% of the unlimited amount, roughly $20,000.

Worked example 4 — MFJ non-SSTB consulting firm above the ceiling, modest wages

Wait — consulting is an SSTB. Let's switch to a non-SSTB scenario. An MFJ couple operates a non-SSTB business (say, a manufacturing operation) with $600,000 of taxable income, $400,000 of QBI, $100,000 of W-2 wages paid by the business, and $0 of UBIA. MFJ phase-in ceiling is $483,900 — $600K is above.

• 20% × QBI: $400,000 × 20% = $80,000 (tentative)
• Wage limit (primary): 50% × $100,000 = $50,000
• Wage limit (alternative): 25% × $100,000 + 2.5% × $0 = $25,000
• Wage limit: max($50,000, $25,000) = $50,000
• 20% × TI: $600,000 × 20% = $120,000 (overall-limit ceiling, not binding)
• Deduction: min($80,000, $50,000, $120,000) = $50,000

The wage limit binds — the deduction drops from the tentative $80,000 to $50,000. The couple lost $30,000 of potential deduction (~$7,500 of federal tax at their 25% marginal bracket) because the business is W-2-light.

Worked example 5 — same as 4, but with $500K UBIA (still binds primary)

Same facts as Example 4 but the business has $500,000 of UBIA (say, machinery on the floor):

• Wage limit (primary): 50% × $100,000 = $50,000
• Wage limit (alternative): 25% × $100,000 + 2.5% × $500,000 = $25,000 + $12,500 = $37,500
• Wage limit: max($50,000, $37,500) = $50,000
• Deduction: still $50,000

The alternative formula didn't help — primary still wins. The 2.5% × UBIA component only changes the answer when it lifts the alternative above the primary.

Worked example 6 — $2M UBIA tips the alternative over the primary

Same facts but now the business has $2,000,000 of UBIA:

• Wage limit (primary): 50% × $100,000 = $50,000
• Wage limit (alternative): 25% × $100,000 + 2.5% × $2,000,000 = $25,000 + $50,000 = $75,000
• Wage limit: max($50,000, $75,000) = $75,000
• Deduction: min($80,000, $75,000, $120,000) = $75,000

The UBIA component finally tips the alternative over the primary. The couple's deduction rises by $25,000 (the difference between $75K and $50K) — roughly $6,250 of federal tax savings at their marginal bracket. This is exactly the relief Congress intended for capital-intensive businesses.

TCJA sunset and the 2026 status

IRC § 199A(i) originally sunset the deduction for tax years beginning after December 31, 2025. As of this calculator's last-reviewed date, current-law continuation assumes Congress has extended the deduction — most likely under the One Big Beautiful Bill Act or comparable TCJA-continuation legislation. The political consensus to keep § 199A has been strong on both sides because ~25 million pass-through filers benefit.

The calculator's post-sunset toggle flips the deduction to $0 to model the no-extension scenario. If you are planning around 2026 returns, monitor the legislative status — a year-end retroactive extension is common, but it leaves a window of planning uncertainty in mid-year. Conservative practitioners model both scenarios.

Aggregation rules

Under Treas. Reg. § 1.199A-4, a taxpayer can elect to aggregate multiple qualified trades or businesses into a single QBI computation, combining W-2 wages and UBIA across all aggregated entities. Aggregation is valuable when one business has high QBI but low wages/UBIA (limiting the deduction) and another has high wages/UBIA but lower QBI (the limit would otherwise go unused).

Requirements: (a) the same person or group directly or indirectly owns 50%+ of each business for the majority of the year, (b) the businesses share two of three (products/services, facilities, business elements like centralized HR/legal/accounting), and (c) NONE of the aggregated businesses is an SSTB. The election is reported on Form 8995-A and is irrevocable for the year.

Rental real estate safe harbor

Rental real estate qualifies for § 199A only if it rises to the level of a § 162 trade or business — a fact-intensive determination. Rev. Proc. 2019-38 provides a safe harbor: a rental real estate enterprise is treated as a § 162 trade or business for § 199A purposes if (a) separate books and records are maintained, (b) at least 250 hours of rental services per year are performed (by the owner, contractors, or employees), and (c) contemporaneous records of those hours are kept — a calendar, log, or timesheet, NOT a year-end reconstruction.

Triple-net leased property does not qualify under the safe harbor. Mixed-use properties where the owner also uses the property as a personal residence do not qualify. Outside the safe harbor, taxpayers can still argue § 162 status on the facts — but the safe harbor is the conservative path.

Common errors

• Including W-2 wages from an unrelated employer in QBI — they are NOT QBI for the wage-earner.
• Forgetting that the W-2 the S-corp owner pays themselves is excluded from QBI but DOES count toward the wage limit.
• Including guaranteed payments to partners in QBI — explicitly excluded under § 199A(c)(4).
• Forgetting to strip net capital gains and qualified dividends out of the overall-limit base.
• Treating real estate brokerage as an SSTB (it isn't — only securities/commodities brokerage is).
• Treating engineering or architecture as an SSTB (they are NOT).
• Missing the contemporaneous-record requirement for the rental safe harbor.
• Failing to make the aggregation election in the first year and then trying to add it retroactively for a closed year.

Statute citations

• IRC § 199A(a) — 20% deduction headline rule
• IRC § 199A(b)(2) — W-2 wage and UBIA limit
• IRC § 199A(b)(3) — non-SSTB phase-in
• IRC § 199A(d)(2)(A) — SSTB definition
• IRC § 199A(d)(3) — SSTB phase-in
• IRC § 199A(e)(2) — threshold amounts (indexed)
• IRC § 199A(e)(3) — net capital gain definition
• IRC § 199A(i) — sunset clause (post-2025)
• Treas. Reg. § 1.199A-1 through § 1.199A-6 — implementing regulations
• Rev. Proc. 2019-38 — rental real estate safe harbor
• IRS Form 8995 / Form 8995-A — reporting
• Pub. L. 115-97 § 11011 — TCJA enactment

Important caveats

This is a planning tool, not legal or tax advice. It does not model aggregation under Treas. Reg. § 1.199A-4 (the user supplies pre-aggregated wage and UBIA figures), the rental real estate safe harbor under Rev. Proc. 2019-38 (the user supplies QBI from already-determined qualified businesses), the patrons-of-agricultural-cooperatives carve-out under § 199A(g), or qualified REIT dividends and qualified PTP income (separate 20% deduction under § 199A(b)(1)(B), not subject to the wage limit). The 2026 thresholds reflect current-law continuation; actual indexed thresholds for 2026 may shift slightly when the IRS issues the official inflation-adjustment revenue procedure for the year. Consult a CPA or tax attorney before filing.