Form 1120

U.S. Corporation Income Tax Return

Filing taxes can be a daunting process, especially for corporations obligated to submit a 1120 tax form. This comprehensive guide is designed to demystify the 1120 form, ensuring you're well-equipped with the knowledge to file your corporate taxes accurately and effectively.

What is a 1120 Form?

The 1120 form, also known as the U.S. Corporation Income Tax Return, is a document that corporations are required to fill out and submit to the Internal Revenue Service (IRS) annually. This form is used by the IRS to calculate and tax a corporation's taxable income.

  • Purpose and Significance: The primary purpose of the 1120 form is to report the corporation's income, gains, losses, deductions, and credits. It plays a vital role in determining the income taxes the corporation owes to the federal government.
  • Components of the Form: The 1120 form includes sections for reporting income, deductions, and tax computations. There are schedules attached to the form where corporations can detail information about their assets, liabilities, and shareholders' equity.

Who Needs a 1120 Form?

Corporations, including LLCs that elect to be taxed as corporations, are required to file a 1120 form.

  • Criteria: The 1120 form applies to domestic corporations that engage in any business activity in the United States.
  • Obligations: Corporations must file this form regardless of whether they operated at a loss or gain during the tax year.
  • Deadlines: The deadline to submit the 1120 form is the 15th day of the fourth month following the end of the corporation's fiscal year. For corporations that follow a calendar year, the deadline is April 15.

How to Read and Understand the 1120 Form

Understanding the 1120 form requires familiarity with its sections, common terms, and figures.

  • Breakdown: The form starts with gross receipts or sales and encompasses deductions such as salaries and wages, rents, taxes, and other expenses directly related to the business operations.

How to Get Your 1120 Form

The most reliable place to get an updated 1120 form is directly from the IRS.

  • Procedures: Corporations can either download the form online or request a physical copy via mail.
  • Direct Link: For downloading 1120 forms, visit the IRS page at

Common Mistakes and How to Avoid Them

Errors when filling out the 1120 form can lead to delays or increased scrutiny from the IRS.

  • Common Errors: Misreporting income, overlooking deductions, and incorrectly calculating the tax due are frequent mistakes.
  • Tips: To avoid these errors, double-check all entries, maintain thorough records, and consider using tax software or consulting with a tax professional.

1120 Form and Tax Filing

The 1120 form significantly impacts the tax filing process for corporations.

  • Role in Tax Returns: It determines the corporation’s tax liability or refund and is the primary document the IRS reviews during the auditing process.
  • Possible Refunds: If the paid estimated taxes exceed the actual tax liability calculated on the 1120 form, the corporation could be eligible for a refund.

FAQ Section

Q1: Who is required to file the 1120 tax form?
A1: Corporations, including LLCs electing to be taxed as a corporation, must file the 1120 form.

Q2: When is the 1120 form due?
A2: It's due by the 15th day of the fourth month following the end of the corporation’s fiscal year. For calendar year corporations, this is April 15.

Q3: Can I file the 1120 form electronically?
A3: Yes, corporations can file electronically through the IRS e-file system.

Q4: What happens if I file the 1120 form late?
A4: Late filings may result in penalties and interest charges on any unpaid tax.

Q5: Do I need a CPA to file a 1120 form?
A5: While it's not mandatory, consulting a CPA or tax professional can help ensure accuracy and compliance.


Navigating the complexities of the 1120 tax form is crucial for corporations to ensure compliance and avoid potential fines. This guide serves as a comprehensive resource to understand, prepare, and file your 1120 form accurately. Remember, when in doubt, consulting with a tax professional can provide personalized advice and peace of mind.

For further information and to download the 1120 form, visit the official IRS website:

This guide aims to empower corporations with the knowledge needed to tackle their 1120 tax form confidently. Remember, thorough preparation and understanding can simplify the tax filing process, allowing you to focus on what truly matters: growing and managing your business.

Always refer to the IRS website or a tax professional for the most accurate and up-to-date information. provides general information and software tools for tax preparation; however, it does not offer personalized tax, legal, or professional advice. It's recommended to consult with a qualified professional for specific advice related to your financial situation.