C-Corporation Federal Tax Calculator
Calculator limitation: This tool estimates regular federal corporate income tax at 21% from the taxable-income amount you enter. It does not calculate every Form 1120 deduction, credit, NOL limitation, special tax, international provision, or CAMT liability.
Executive Summary & Statutory Framework
Under 26 U.S.C. Section 11, the regular federal corporate income-tax rate for domestic C corporations is 21% of taxable income. This is the regular corporate income-tax rate; it does not mean every corporation's final federal tax liability is always exactly 21% of an initial income figure because deductions, credits, NOLs, special taxes, and other provisions can affect the final liability.
Key corporate tax rules include:
- Taxable Income: The 21% rate applies to taxable income, not gross revenue. Form 1120 is used to report income, deductions, credits, and the resulting corporate income-tax liability.
- Form 1120 Filing Mandate: All C-Corps must file IRS Form 1120 annually, even if no taxable income was earned.
- Double Taxation Structure: A C corporation generally pays corporate income tax, and shareholders may separately be taxed when corporate earnings are distributed as dividends.
- Estimated Tax: Corporations generally must make installment payments when expected total tax, after applicable credits, is $500 or more. Payments are generally due in the 4th, 6th, 9th, and 12th months of the tax year.
- Corporate Alternative Minimum Tax: Certain large corporations may be subject to CAMT, a separate 15% minimum-tax regime based on adjusted financial statement income. This calculator does not model CAMT.
- International Ownership: Foreign ownership does not by itself change a domestic corporation into a foreign corporation, but foreign-owned corporations can have additional information-reporting, withholding, transfer-pricing, and international tax obligations.
Corporate Tax Regulatory Summary
| Statutory Citation | Subject Area | Compliance Requirement |
|---|---|---|
| 26 U.S.C. § 11 | Federal Corporate Tax Rate | Flat 21% rate on net taxable corporate income. |
| IRS Form 1120 | Corporate Income Tax Return | Generally due the 15th day of the 4th month after the end of the corporation's tax year; April 15 for calendar-year corporations, subject to applicable exceptions and extensions. |
| IRS Form 1120-W / IRC §6655 | Estimated Tax | Form 1120-W is a worksheet used to determine required installments; qualifying corporations generally make installment payments when expected total tax after applicable credits is $500 or more. |
| 26 U.S.C. §§ 531–537 | Accumulated Earnings Tax | 20% tax on accumulated taxable income in qualifying cases involving accumulation beyond reasonable business needs for the purpose of avoiding shareholder income tax. |
| 26 U.S.C. §§ 55, 56A, 59 | Corporate Alternative Minimum Tax | 15% tentative minimum tax based on adjusted financial statement income for applicable corporations, subject to statutory calculations and credits. |
Live Expat FX Tool 0% Hidden Spread
International Money Transfer & FX Rates
Sending funds for tuition, rent, or immigration fees? Retail banks sneak 2.5%–4% into exchange rates. Check today's real mid-market rate first.
High-Street Banks:~3.5% Hidden Markup
Wise Mid-Market:Zero Markup (Google Rate)
⚡ Free live comparison • 50+ currencies supported
Related Corporate Guides
Related US Tools & Guides
Frequently Asked Questions (FAQ)
Under 26 U.S.C. Section 11 (as enacted under the Tax Cuts and Jobs Act), the U.S. federal corporate income tax rate is a flat 21% applied to taxable income earned by domestic C-Corporations and foreign corporations operating in the U.S.
Domestic corporations generally file Form 1120. Foreign corporations engaged in a U.S. trade or business may need to file Form 1120-F. A 25% foreign-owned U.S. corporation generally must file Form 5472 when it has a reportable transaction with a related party, subject to the applicable exceptions. A foreign-owned U.S. disregarded entity with a Form 5472 filing obligation generally files Form 5472 attached to a pro forma Form 1120.
For a calendar-year C corporation, Form 1120 is generally due April 15, the 15th day of the fourth month after the end of the tax year. Corporations generally must make installment payments of estimated tax when they expect their total tax, after applicable credits, to be $500 or more. For a calendar-year corporation, the installments are generally due April 15, June 15, September 15, and December 15. Form 1120-W is a worksheet used to help determine required installments; it is not the payment mechanism.
A C corporation is a separate taxable entity and generally pays federal income tax at the 21% corporate rate. When the corporation distributes earnings as dividends, the shareholder may also owe tax on the dividend. The shareholder-level rate depends on the shareholder, the type of dividend, and other applicable rules. The 3.8% Net Investment Income Tax can apply to certain individuals, estates, and trusts who satisfy the statutory requirements; it is not automatically imposed on every dividend or every shareholder. Pass-through entities generally have different federal income-tax treatment because their income is generally passed through to their owners rather than taxed under the regular C-corporation regime.
Under IRC §531, a 20% accumulated earnings tax can apply to a corporation's accumulated taxable income when the corporation accumulates earnings and profits beyond the reasonable needs of the business for the purpose of avoiding income tax on its shareholders. The rule is more specific than simply taxing any retained earnings above a particular amount, and bona fide business needs and the accumulated earnings credit must be considered.
A corporation created or organized in the United States or under U.S. or state law is generally a domestic corporation for federal tax purposes. A domestic C corporation is generally subject to U.S. federal income tax on its worldwide taxable income, and foreign ownership of its shares does not by itself convert the corporation into a foreign corporation. However, international provisions, foreign tax credits, withholding, transfer-pricing rules, and other rules can affect the actual tax liability.
No. It is a simplified regular corporate income-tax estimate. Actual Form 1120 tax liability can involve deductions, net operating losses, tax credits, special deductions, other taxes, and other provisions that are not modeled by this calculator.
CAMT is a separate federal minimum-tax regime that generally applies to certain large corporations based on adjusted financial statement income. The CAMT rate is 15% of adjusted financial statement income for applicable corporations, subject to the statutory calculation and credits. This simple 21% calculator does not calculate CAMT.
No. Form 1120-W is a worksheet used to help determine a corporation's estimated tax and required installments. Corporate estimated tax payments are made through the applicable electronic payment system, generally EFTPS or another permitted electronic payment method.
Official IRS References
• IRS About Form 1120: irs.gov/form1120
• IRS Publication 542 (Corporations Tax Guide): irs.gov/p542
• IRS Form 1120-W (Estimated Tax for Corporations): irs.gov/form1120w
• IRS Corporate Alternative Minimum Tax (CAMT): irs.gov/camt
• IRS Form 5472: irs.gov/form5472