Corporate Income Tax Calculator
Estimate regular federal C-corporation tax from Form 1120 taxable income, then reconcile credits, other taxes and payments.
Estimated amount due
$52,500Total federal tax
$52,500Effective rate
21.0%Scope: regular Form 1120 tax only. This estimate does not calculate corporate alternative minimum tax, BEAT, recapture taxes, consolidated-return adjustments or state corporate/franchise taxes.
Form 1120 calculation sequence
- Start with taxable income after federal deductions and any net-operating-loss rules.
- Multiply regular taxable income by 21%.
- Subtract allowable credits, then add other taxes shown on Schedule J.
- Compare total tax with estimated payments, extension payments and refundable credits.
Corporate income tax questions
What is corporate income tax?
Corporate income tax is a tax imposed on the taxable income of a corporation. A domestic C corporation generally reports its federal income, deductions, credits and tax on Form 1120.
What is the US federal corporate tax rate in 2026?
The regular federal income-tax rate for a C corporation is a flat 21% of taxable income. Corporate alternative minimum tax, BEAT and other special taxes can change the final liability for corporations within those regimes.
Does the 21% rate apply to S corporations?
Usually no. An S corporation generally passes income, deductions and credits through to shareholders instead of paying regular federal corporate income tax, although entity-level taxes can apply in limited situations and states may impose separate charges.
Does this calculator include state corporate tax?
No. States use separate corporate income, franchise, gross-receipts or margin-tax systems. This calculator estimates only the regular federal Form 1120 layer.
Are tax credits allowed to create a negative regular tax?
The calculator limits entered credits to regular tax. Refundable credits, estimated payments and deposits belong in the payments field and may create an overpayment.
Does this calculate corporate alternative minimum tax?
No. Applicable corporations use Form 4626 for the corporate alternative minimum tax based on adjusted financial statement income. This calculator is intentionally limited to regular Form 1120 tax.
Sources
Related Calculators
R&D Tax Credit Calculator
Form 6765 regular and ASC research credit estimates from qualified expenses
Net Operating Loss Calculator
NOL deduction, 80% limit, taxable income, and carryforward by vintage
Corporate Tax Rate 2026
Federal C-corporation 21% rate, worked examples, and separate CAMT scope
Corporate Tax Deadline 2026
Form 1120 due dates, fiscal-year rule, Form 7004 extension, and payment timing
Quarterly Estimated Tax
Four installments (4/15, 6/15, 9/15, 1/15), safe harbor 90%/100%