Use the calculator below to estimate your Section 199A deduction using the new formula from the Big Beautiful Tax Bill of 2025.

Note: More detailed instructions appear below the calculator but you can probably use numbers from your 2024 or 2025 tax returns to calculate the new formula’s effect on your Section 199A deduction.

const W2_limit = Math.max(0.5 * W2_N, 0.25 * W2_N + 0.025 * UB_N);
const deduction_non_sstb = Math.min(D * QBI_N, W2_limit);
const all_qbi = QBI_N + QBI_S;
const threshold = FS === “M” ? MT : ST;
const limitation = 0.75 * (TI – threshold);
const deduction_all_tb = D * all_qbi – Math.min(D * all_qbi, limitation);
const greater_deduction = Math.max(deduction_non_sstb, deduction_all_tb);
const final_deduction = Math.min(D * TI, greater_deduction);

document.getElementById(“non_sstb_deduction”).innerText = “$” + deduction_non_sstb.toFixed(2);
document.getElementById(“all_tb_deduction”).innerText = “$” + deduction_all_tb.toFixed(2);
document.getElementById(“greater_deduction”).innerText = “$” + greater_deduction.toFixed(2);
document.getElementById(“final_deduction”).innerText = “$” + final_deduction.toFixed(2);
}

Using the Big Beautiful Section 199A Calculator

To use the Section 199A calculator, follow these steps:

1. (Optional) Replace my very rough estimates of the thresholds for phasing in the Section 199A limitations–$200,000 for single filers and $400,000 for married filers–with better numbers if you have them. (The Treasury will provide better numbers for 2026 later in 2025 if the Big Beautiful Tax bill passes and thereby perpetuates the Section 199A deduction.)
2. Enter an M or an S into the Filing Status box to incidate your tax return filing status.
3. Enter or estimate your taxable income using the Taxable Income box.
4. Describe your non specified service trades or businesses qualified business income, W-2 wages and depreciable property boxes. Note that if you’ve aggregated your non-SSTB businesses, the calculator should work fine. If you have multiple, un-aggregated businesses, it may not work accurately. Sorry.
5. Provide your total specified service trade or business (SSTB) income. You should be able to aggregate all your SSTBs into a single number.
6. Click Calculate.

Tip: For more information about how the new Section 199A formula works, take a peek at this blog post: The New Big Beautiful Section 199A Deduction.

A final caution: Assuming the Big Beautiful Tax bill passes Congress, it’ll be months before the Treasury can issue updated regulations. Thus, consider the Big Beautiful Section 199A calculator’s numbers rough estimates.

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