Corporate Tax Calculator
Work out your US C-corporation tax for 2026 — the flat 21% federal corporate income tax plus your state corporate income tax, with the combined total liability and effective tax rate.
Rates valid for 2026 · Official source: law.cornell.edu
How US corporate tax works in 2026
In the United States, the headline “corporation tax” is the federal corporate income tax imposed on C corporations under Internal Revenue Code (IRC) §11. Since the Tax Cuts and Jobs Act took effect in 2018, this is a flat 21% of taxable income (IRC §11(b)) — with no graduated brackets, no small-profits rate, no marginal relief and no surcharge or solidarity levy. Every C corporation pays the same 21% federal rate for 2026, whether its taxable income is $10,000 or $10 million.
US corporate tax is a stacked system, though. On top of the 21% federal layer, most states levy their own state corporate income tax (CIT) on income apportioned to that state. State rates vary widely — from 0% in states such as South Dakota and Wyoming (and, in practice, Texas, Washington, Ohio and Nevada, which use other bases) up to about 11.5% in New Jersey. Some states replace the income tax entirely with a gross-receipts, franchise or margin tax. A handful of cities add a local corporate tax as well (for example New York City’s Business Corporation Tax), though the calculator focuses on the federal and state layers.
Rates for 2026
The calculator stacks a fixed 21% federal layer with a selectable state layer. The federal figure is exact and applies to every C corporation; the state figure changes with the state you choose. The representative states below use their 2026 top or flat CIT rate (Tax Foundation, 2026):
| Tax | Rate / band |
|---|---|
| Federal Corporate Income Tax | 21% |
| State Corporate Income Tax | 0% |
Selectable states in the calculator include California (8.84% flat), New York (7.25% top), Florida (5.5%), Illinois (9.5%, combining a 7.0% CIT with a 2.5% personal-property replacement tax), Pennsylvania (7.99% flat, currently phasing down), New Jersey (11.5% top marginal — the highest in the US) and North Carolina (2.0% flat — the lowest). Texas, Washington, Ohio and Nevada are shown as 0% because they levy a gross-receipts or margin tax rather than a corporate income tax, and that separate levy is not modelled here.
Worked example
Suppose your C corporation has $500,000 of taxable income for 2026 and operates in California:
- Federal tax: $500,000 × 21% = $105,000
- California state CIT: $500,000 × 8.84% = $44,200
- Total corporate tax: $105,000 + $44,200 = $149,200
- Effective tax rate: $149,200 ÷ $500,000 = 29.84%
Change the state and the result moves with it. The same $500,000 would owe $105,000 federal only (a 21% effective rate) in a no-CIT state such as South Dakota, or $105,000 + $57,500 = $162,500 (32.5% effective) in New Jersey. Enter your own figure in the calculator above to see the split instantly.
How states vary
State corporate taxation falls into four broad patterns, and the right treatment depends entirely on where you do business:
- Income-tax states (most states) charge a flat or graduated rate on state-apportioned taxable income — for example California, New York, Florida and New Jersey.
- Gross-receipts / margin states tax revenue rather than net profit, with little or no expense deduction — Texas (Franchise/Margin Tax), Washington (B&O), Ohio (Commercial Activity Tax) and Nevada (Commerce Tax).
- Franchise / minimum-tax states add a fee on capital, shares or assumed par (for example Delaware’s franchise tax, or California’s $800 minimum tax) on top of, or instead of, the income tax.
- No-tax states — South Dakota and Wyoming levy neither a corporate income tax nor a gross-receipts tax.
A business operating in more than one state does not pay the full rate everywhere. Instead, income is apportioned to each state — typically by a single-sales-factor or three-factor formula — and only the apportioned share is taxed at that state’s rate. The calculator applies a single selected state’s rate to your full taxable income; a multi-state business should apportion first.
Federal specifics
Because the federal rate is a single flat 21%, there are no brackets, no small-profits rate and no marginal relief to model — unlike the UK system. A few federal add-ons apply to specific taxpayers:
- CAMT (Corporate Alternative Minimum Tax): a 15% book-minimum tax on adjusted financial statement income (AFSI) for corporations averaging over $1 billion of AFSI over three years (IRC §55/§59). It remains in force for 2026 but is out of scope for general filers.
- BEAT (Base Erosion and Anti-abuse Tax): a minimum tax targeting large multinationals with significant deductible payments to foreign affiliates — rising to 10.5% for tax years beginning after 31 December 2025.
- OBBBA (2025): the One Big Beautiful Bill Act made 100% bonus depreciation permanent for qualified property placed in service after 19 January 2025, and restored immediate expensing of domestic research (R&D) for tax years beginning after 31 December 2024 (foreign R&D is still amortised over 15 years).
Deductions and losses
Federal taxable income is revenue minus cost of goods sold and ordinary business deductions — including depreciation, §179 expensing, charitable contributions (capped at 10% of taxable income) and the dividends-received deduction (50%/65%/100% tiers). Two rules matter most for larger companies:
- Net operating losses (NOLs): post-2017 NOLs cannot generally be carried back, are carried forward indefinitely, and can offset only 80% of taxable income in a carryforward year (IRC §172).
- Business-interest limitation (§163(j)): deductible net business interest is capped, and for years beginning in 2026 the cap reverts to the more generous EBITDA base.
S corporation vs C corporation
Only C corporations pay the entity-level 21% federal tax modelled here. S corporations (Form 1120-S), partnerships and most LLCs are pass-through entities — profits flow through to the owners’ personal returns and there is no separate federal corporate income tax at the entity level. If you are choosing an entity structure, compare the C-corp result here with your expected personal-rate outcome.
Related calculators
Planning payroll or personal tax alongside your corporate liability? Try the US salary calculator for take-home pay and the US income tax calculator for personal federal and state tax. To compare neighbouring regimes, see the Canada corporation tax calculator and the Mexico corporation tax calculator.
Last updated and disclaimer
Figures reviewed for tax year 2026. Last updated July 2026 (config date 2026-07-01). This calculator is a general guide and not tax advice — rates, apportionment and eligibility for specific deductions vary by state and circumstance. Verify your figures with a CPA or the IRS Form 1120 instructions before filing.