calculate_business_tax

One employee's annual wages, for the employer-side payroll-tax target (§ 3111 FICA + FUTA). In dollars.

Qualified research expenses for the current year (§ 41(b); § 41(d) qualification attested). In dollars.

Average annual qualified research expenses over the 3 preceding years — 0 means no prior QREs (the 6% startup rate of § 41(c)(4)(B) applies). In dollars.

Number of members (owners) of the LLC — one member defaults to disregarded-entity treatment, two or more to partnership (Treas. Reg. § 301.7701-3(b)(1)).

Number of shareholders, counting married couples and § 1361(c)(1) family members as one (§ 1361(b)(1)(A): may not exceed 100).

The C corporation's taxable income BEFORE the § 250 deduction, if already computed — used as-is when provided. Leave at 0 to have the engine compute it from corpGrossIncome and the deduction components (charitable/DRD/NOL machinery). CONTRACT: the § 250 deduction is computed separately from corpFDDEI/corpNCTI and subtracted by the tax rule — an AS-FILED Form 1120 line 30 already nets out § 250, so when providing corpFDDEI/corpNCTI enter the pre-§ 250 amount here (line 30 plus the § 250 deduction as filed), never the net. In dollars.

The corporation's gross income (§ 61), INCLUDING any dividends received, any § 951 subpart F and § 951A NCTI/GILTI inclusions with their § 78 gross-ups (§ 951A(a) is a gross-income INCLUSION — the § 250 deduction is computed separately from corpNCTI), and any § 245A-eligible foreign-sub dividends. In dollars.

Ordinary business deductions (salaries, rents, prior-year amortization, …) — everything EXCEPT charitable contributions, the dividends-received deduction, and NOLs, which have their own limited rules. Enter compensation already limited by § 162(m) (no deduction for a covered employee's remuneration over $1,000,000 at a publicly held corporation — not modeled, attested). In dollars.

The corporation's charitable contributions — current-year gifts plus allowable prior-year § 170(d)(2) carryovers being used (both subject to the same ceiling and, from 2026, the OBBBA floor). In dollars.

Dividends received from other taxable domestic corporations (§ 243 DRD; must also be included in corpGrossIncome). Enter only dividends on stock meeting the § 246(c) holding period (held more than 45 days during the 91-day window around the ex-dividend date; 90/181 for certain preferred) — attested; § 1059 extraordinary-dividend basis reduction not modeled. In dollars.

Net operating loss carryforward available this year (§ 172: deduction limited to 80% of taxable income before the NOL; post-TCJA, no carrybacks). In dollars.

Tax shown on the corporation's preceding-year return (§ 6655(d) prior-year prong; unavailable if that year showed zero tax or was short). In dollars.

TY2025: foreign-derived intangible income (FDII); TY2026+: foreign-derived deduction eligible income (FDDEI, OBBBA — QBAI abolished). The § 250 deduction applies 37.5% (2025) / 33.34% (2026+). In dollars.

TY2025: the § 951A GILTI inclusion (with its § 78 gross-up); TY2026+: net CFC tested income (NCTI, OBBBA). The § 250 deduction applies 50% (2025) / 40% (2026+). The inclusion itself is GROSS INCOME (§ 951A(a)) — it must also be in corpGrossIncome with its § 78 gross-up; this fact drives only the § 250 deduction and FTC basket. The per-CFC tested-income aggregation is not modeled. In dollars.

Aggregate current-year § 38(b) general business credits (e.g. the § 41 research credit target's result) — limited under § 38(c). In dollars.

Creditable foreign income taxes in the § 904(d) GENERAL basket. In dollars.

Foreign-source taxable income in the general basket (§ 904 limitation numerator; § 861 expense allocation attested). In dollars.

Foreign taxes attributable to the § 951A basket (GILTI/NCTI) — the § 960(d) deemed-paid credit takes the 80% (2025) / 90% (2026+, OBBBA) allowance, no carryovers. In dollars.

Base erosion tax benefits for the year (§ 59A(c)(2)) — include the base-erosion percentage of any NOL deduction (§ 59A(c)(1)(B)). Added back to reach modified taxable income. In dollars.

The corporation's capital gains for the year (§ 1211(a): losses offset only these; net gain is ordinary-rate income for a corporation). In dollars.

The corporation's capital losses for the year, including prior-year § 1212(a) carryovers being used (allowed only to the extent of capital gains). In dollars.

Average indebtedness percentage (0-100) of debt-financed portfolio stock (§ 246A) — reduces the 50%/65% DRD proportionally; 0 = not debt-financed.

Corporate taxable income for the first 3 months (§ 6655(e) annualization, installments 1-2). In dollars.

Corporate taxable income for the first 6 months (§ 6655(e) annualization, installment 3). In dollars.

Corporate taxable income for the first 9 months (§ 6655(e) annualization, installment 4). In dollars.

The S corporation's passive investment income — royalties, rents, dividends, interest, annuities (§ 1375(b)(3)). In dollars.

The S corporation's gross receipts for the year (§ 1375). In dollars.

Passive investment income net of directly-connected deductions (§ 1375(b)(2)). In dollars.

The S corporation's taxable income computed as if it were a C corporation (§§ 1374(b)(1)/1375(b)(1)(B) cap). In dollars.

Net recognized built-in gain during the § 1374(d)(7) 5-year recognition period after a C-to-S conversion (0 if the period has passed or there was no conversion). In dollars.

3-year-average adjusted financial statement income (§ 56A) — over $1 billion triggers the corporate AMT, which this engine refuses to approximate. In dollars.

Cost of qualified § 168(k) property acquired AND placed in service this year (acquired after January 19, 2025 — 100% bonus depreciation, OBBBA-permanent). EXCLUDE passenger automobiles (the § 280F luxury-auto caps are not modeled) and anything entered in corpSection179Cost. In dollars.

Cost of § 179 property the corporation elects to expense — including qualified real property (roofs, HVAC, fire/security systems on nonresidential real property, § 179(d)(1)(B)(ii)) that § 168(k) cannot reach. Must NOT also be in corpEquipmentPurchases; EXCLUDE passenger automobiles and sport utility vehicles (the § 280F caps and the § 179(b)(5) SUV cap are not modeled). In dollars.

Fair market value of the corporation's own stock repurchased (§ 317(b) redemptions and economically similar transactions) during the taxable year, for the § 4501 excise. In dollars.

Fair market value of stock issued by the corporation during the taxable year (including to employees) — netted against repurchases under § 4501(c)(3). In dollars.

Foreign-source portion of dividends received from specified 10-percent-owned foreign corporations, eligible for the § 245A participation-exemption DRD (100%). Must also be included in corpGrossIncome. Attested by entry: US-shareholder status, NOT a § 245A(e) hybrid dividend, and the § 246(c)(5) 365-day holding period met; no foreign tax credit is allowed for the deducted portion (§ 245A(d)) — keep these taxes out of the FTC inputs. In dollars.

Domestic research or experimental expenditures — currently deductible under § 174A (OBBBA, permanent from 2025). In dollars.

FOREIGN research or experimental expenditures paid this year — capitalized and amortized over 15 years (§ 174; first-year deduction is 1/30 under the midpoint convention). In dollars.

Business interest expense (§ 163(j): limited to 30% of EBITDA-based ATI unless the § 448(c) gross-receipts test is met). In dollars.

3-year-average annual gross receipts (§ 448(c) test: $31M for 2025, $32M for 2026 — at or below it the § 163(j) limit does not apply). In dollars.

Dividends paid during the year (the § 561 dividends-paid deduction for the accumulated-earnings computation). In dollars.

Accumulated earnings and profits at the close of the PRECEDING year (§ 535(c)(2) minimum-credit offset). In dollars.

Earnings retained for the reasonable needs of the business (§§ 535(c)(1), 537 — documented needs; part of the accumulated earnings credit). In dollars.

Personal holding company income (§ 543: dividends, interest, royalties, annuities, certain rents). In dollars.

Adjusted ordinary gross income (§ 543(b)(2)) — the 60% test base. In dollars.

Undistributed personal holding company income (§ 545: taxable income adjusted, less federal taxes and the dividends-paid deduction). In dollars.