Corporate Tax Calculator
Only applies if 3-year average over $1B
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How to use
- 1 Enter gross revenue from your corporate books (revenue from Form 1120 line 1a).
- 2 Enter total deductible expenses (cost of goods sold + operating expenses + interest + depreciation + officer comp). Pre-OBBBA you'd have to amortize R&E over 5 years; post-OBBBA you can immediately expense domestic R&E.
- 3 Select your state of incorporation/operation (or primary nexus). Calculator applies the top marginal state corporate rate. Multi-state operations require apportionment formula (sales/payroll/property).
- 4 For corporations with 3-year average AFSI > $1 billion, enter the AFSI 3-yr avg to compute CAMT 15% minimum tax (only kicks in if greater than regular 21% × taxable income).
- 5 For publicly-traded companies, enter net stock buybacks for the 1% excise tax computation (de minimis under $1M is exempt). Click Calculate to see all four tax layers, total tax, and effective rate.
About Corporate Tax Calculator
FAQ
Q What is the federal corporate income tax rate in 2026?
21% flat rate on all C-corp taxable income, made permanent by the Tax Cuts and Jobs Act of 2017. The OBBBA (signed July 2025) preserved this rate. Personal Service Corporations also pay 21% (the prior 35% PSC rate was eliminated by TCJA).
Q Which state has the highest corporate income tax?
New Jersey at 11.5% (top marginal rate, with surtax on income over $10M). Minnesota 9.8%, Illinois 9.5%, Alaska 9.4%, Vermont 8.75%, California 8.84%, and Maine 8.93% round out the top tier. Combined with 21% federal, top earners face ~32-34% effective rate.
Q Which states have no corporate income tax?
Six states: Nevada, Ohio, South Dakota, Texas, Washington, Wyoming. BUT four of them impose a gross receipts tax instead (NV Commerce Tax, OH Commercial Activity Tax, TX Franchise/Margin Tax, WA B&O Tax). Only South Dakota and Wyoming truly have zero state tax on corporations.
Q What is the Corporate Alternative Minimum Tax (CAMT)?
A 15% minimum tax on Adjusted Financial Statement Income (AFSI) for corps averaging over $1 billion in AFSI over 3 years. Enacted by the Inflation Reduction Act of 2022; applies to roughly 150 mega-corporations. Paid only if greater than regular 21% × taxable income.
Q What is the stock buyback excise tax?
1% excise tax on net stock repurchases by publicly traded corporations, enacted by the Inflation Reduction Act of 2022 (IRC §4501). Applies to corps that repurchase over $1 million annually. Reduced by new stock issuances; non-deductible to the corporation. Reported on new Form 7208.
Q How does §174 R&E expensing work in 2026?
OBBBA restored immediate expensing of domestic R&E for tax years beginning after December 31, 2024 (under new §174A). Foreign R&E still must be amortized over 15 years. Major win for tech, biotech, and software companies that had been forced to amortize R&E over 5 years since 2022 (TCJA mandate).
Q How are corporate dividends taxed?
Double-taxed: corporation pays 21% federal on profits, then shareholders pay tax on dividends (qualified rate 0/15/20% LTCG; 3.8% NIIT for high earners). Combined effective rate ~37-50% depending on bracket. S-corp election (pass-through) avoids the corporate level entirely but limits to 100 shareholders and one class of stock.
Q What is the §163(j) interest deduction limit?
Limits business interest deduction to 30% of Adjusted Taxable Income (ATI). Pre-OBBBA, ATI was based on EBIT (excluded depreciation/amortization). OBBBA permanently restored EBITDA-based ATI starting 2025 — adding back depreciation and amortization, which significantly improves the deduction for capital-intensive industries (manufacturing, real estate, infrastructure).
Official resources
IRS — About Form 1120 U.S. Corporation Income Tax Return
Internal Revenue Service official Form 1120 page used by C-corps to report income, deductions, and federal corporate tax liability.
IRS — Corporate Alternative Minimum Tax (CAMT) Guidance
Internal Revenue Service official simplified method for determining CAMT applicable corporation status under the $1B test.
Tax Foundation — 2026 State Corporate Tax Rates
Tax Foundation interactive map of corporate income tax rates across all 50 states for 2026 planning.
IRS — Stock Buyback Excise Tax Guidance
IRS official page for the 1% Stock Buyback Excise Tax (IRC §4501) including Form 7208 filing requirements.