Section 199A QBI deduction calculator

Section 199A QBI deduction: the pass-through business tax break

The Section 199A qualified business income deduction allows owners of pass-through businesses — sole proprietors, partnerships, S-corps, and some trusts — to deduct up to 20% of their qualified business income from taxable income. For a business owner in the 22% bracket with $100,000 in net profit, this deduction saves up to $4,400 per year in federal income tax. The rules are complex, with phase-outs, SSTB restrictions, and W-2 wage limitations that kick in at higher income levels.

The basic calculation (below the threshold)

For taxpayers below the income threshold ($191,950 single / $383,900 MFJ in 2024), the calculation is straightforward:

1. Tentative QBI deduction = net qualified business income × 20%
2. Income cap = (taxable income − net capital gains) × 20%
3. QBI deduction = lesser of tentative QBI or income cap

The income cap prevents the QBI deduction from exceeding 20% of all non-capital-gain income, ensuring that business owners and investors in the same bracket pay comparable tax rates.

Phase-out range: $191,950–$241,950 (single) / $383,900–$483,900 (MFJ)

Between the lower and upper thresholds, two restrictions phase in:

• SSTB restriction: For specified service trades or businesses, the allowed QBI phases out linearly from 100% to 0% as taxable income increases from the lower to upper threshold. A consultant with $216,000 in taxable income (halfway through the $50,000 phase-out range for single filers) sees their QBI deduction cut by 50%.
• W-2 wage limitation: For all business types, the deduction cannot exceed the greater of 50% of W-2 wages paid or 25% of wages + 2.5% of qualified property basis. This limitation phases in over the same income range.

Above the upper threshold: non-SSTB businesses

Non-SSTB businesses (contractors, real estate, manufacturing, etc.) can still claim the QBI deduction above the upper threshold, but the W-2 wage limitation applies in full. A sole proprietor with no employees has a W-2 wage limitation of zero — meaning their QBI deduction is zero above the threshold. This is a powerful argument for either (a) hiring employees or (b) converting to an S-corp to generate W-2 wages (from the owner's own salary) that satisfy the wage test.

Interaction with SE tax and retirement contributions

The QBI deduction reduces income tax but not self-employment tax. It is computed after the SE deduction (the deductible half of SE tax) and after retirement plan contributions (SEP-IRA, Solo 401(k)). Maximizing retirement contributions reduces QBI, which reduces the QBI deduction — but the income tax savings from the contribution typically exceed the lost QBI benefit. Always model both together before deciding on contribution amounts.