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QBI Deduction Calculator (Section 199A)

Estimate the 20% Qualified Business Income deduction for pass-through business owners.

Result

Estimated QBI Deduction
$16,000.00

This is a simplified estimate (20% of qualified business income, capped at 20% of taxable income) for filers below the income phase-out threshold. High earners, and owners of "specified service" businesses (law, health, consulting, etc.) above the threshold, face additional wage and property limitations this calculator doesn't model - consult a tax professional if your income is near or above the phase-out range.

About the QBI Deduction

Pass-through business owners got a major new deduction under the 2017 tax reform: up to 20% of qualified business income, deducted straight off taxable income. Our QBI Deduction Calculator estimates that Section 199A deduction using the two limits that govern it.

How It Works

The calculator computes 20% of your qualified business income and separately 20% of your total taxable income before the QBI deduction, then takes whichever is smaller as your deduction. This simplified version applies to filers below the income phase-out threshold; above it, wage and property limitations (and restrictions for specified service businesses) start to apply.

QBI-based amount = QBI × 20% Income-based limit = taxable income × 20% Deduction = min(QBI-based amount, income-based limit)

Formula & Methodology

Section 199A was designed to give pass-through business owners (sole proprietors, partnerships, S-corps) a tax benefit roughly analogous to the flat 21% corporate rate C-Corps received in the same 2017 reform. The deduction is capped at 20% of taxable income specifically to prevent it from ever exceeding 20% of a filer's total income, even in edge cases where QBI itself might be unusually large relative to overall taxable income. Above the income phase-out threshold, the calculation gets considerably more complex: the deduction becomes limited by W-2 wages paid by the business and the unadjusted basis of qualified property, and owners of 'specified service trades or businesses' (law, health, consulting, financial services, and similar fields) can lose the deduction entirely as income rises further past the threshold.

Step-by-Step: Calculating It By Hand

  1. 1Determine your qualified business income: net income from a sole proprietorship, partnership, or S-corp, excluding W-2 wages, capital gains, dividends, and interest.
  2. 2Multiply QBI by 20% to get the QBI-based deduction amount.
  3. 3Calculate your total taxable income before the QBI deduction, then multiply by 20% for the income-based limit.
  4. 4Take the smaller of the two amounts as your estimated deduction.
  5. 5If your taxable income is near or above the phase-out threshold, or your business is a specified service trade, consult a tax professional since wage and property limitations may reduce the deduction further.

Examples

Straightforward case

$80,000 QBI with $95,000 total taxable income → QBI-based amount is $16,000, income-based limit is $19,000, so the deduction is the smaller figure, $16,000.

Income-limited case

The same $80,000 QBI with only $70,000 total taxable income caps the deduction at $14,000 (20% of taxable income), below the $16,000 QBI-based amount.

Advantages

  • Applies both required limits (QBI-based and income-based) rather than just one
  • Flags clearly when the simplified calculation stops being reliable due to phase-outs
  • Useful for a first-pass estimate before a full analysis with wage and property limitations
  • Helps pass-through business owners understand the mechanics behind a valuable deduction

Common Mistakes

  • Assuming the deduction is always exactly 20% of business income without checking the income-based limit
  • Not realizing specified service business owners can lose the deduction entirely at higher income
  • Ignoring the W-2 wage and property limitations that apply above the phase-out threshold
  • Including capital gains, dividends, or W-2 wages paid to yourself in the QBI figure, when none of those qualify

Edge Cases to Watch For

  • Specified service trades or businesses (law, health, consulting, athletics, financial services, and similar) face a full phase-out of the deduction once taxable income clears the upper end of the phase-out range.
  • Above the phase-out threshold, even non-service businesses become limited by the greater of 50% of W-2 wages paid, or 25% of W-2 wages plus 2.5% of qualified property basis - neither of which this simplified calculator models.
  • A business operating at a loss produces negative QBI, which reduces (and can zero out) QBI from other profitable businesses you own before the 20% calculation applies.
  • REIT dividends and qualified publicly traded partnership income get their own 20% QBI-style deduction outside the wage/property limitations, even for high earners.

Common Use Cases

  • Estimating the Section 199A deduction for a sole proprietorship, partnership, or S-corp owner
  • Understanding how the 20%-of-taxable-income limit can cap the deduction below 20% of QBI
  • Deciding whether income is near the phase-out threshold and warrants professional tax planning
  • Comparing QBI deduction value across different business income levels
Written & fact-checked by the Calculateus TeamLast updated August 5, 2026How we verify our formulas

Frequently asked questions

What counts as "qualified business income"?

Generally the net income from a sole proprietorship, partnership, S-corp, or other pass-through business - it excludes W-2 wages you pay yourself, capital gains, dividends, and interest income, which are taxed under their own separate rules.

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Conclusion

The QBI deduction can meaningfully lower a pass-through business owner's tax bill, but it gets complicated fast once income rises near the phase-out range or the business falls into a specified service category. This estimate works well for straightforward cases below the threshold; anyone close to or above it should work through the wage and property limitations with a tax professional.

References