Form 1120: What is a 1120 Tax Form and How to File it?

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Form 1120 is an important tax form used by corporations to report their income and calculate their tax liability. This guide will explain what Form 1120 is, who needs to file it, how to download it, and the steps to file it correctly. Understanding this form is essential for businesses to stay compliant with IRS regulations.

What is Form 1120?

U.S. Corporation Income Tax Return

Form 1120, also known as the U.S. Corporation Income Tax Return, is used by corporations to report their income, losses, gains, and deductions. It helps the IRS determine how much tax a corporation owes. This form is updated annually by the IRS to reflect changes in tax laws.


Different Types of Form 1120

There are various versions of Form 1120 tailored for different types of corporations:

  • Form 1120-F: For Foreign Corporations
  • Form 1120-H: For Homeowners Associations
  • Form 1120-L: For Life Insurance Companies

Each form comes with specific instructions to guide corporations on how to fill them out and the deadlines for submission.


How to Download Form 1120

Steps to Download

To download Form 1120, follow these steps:

  1. Visit the IRS website.
  2. Click on “Forms and Instructions.”
  3. Search for “Form 1120.”
  4. Download the form.

Downloading 1120-S for S Corporations

S corporations should use Form 1120-S to file their income tax returns. This form can also be downloaded from the IRS website using the same steps.


Who Should File Form 1120?

Filing Requirements

All domestic corporations must file Form 1120 unless they are exempt under Section 501. This includes entities that choose to be taxed as corporations. These entities must also file Form 8832 and attach it to Form 1120. Corporations engaged in farming should also file this form to report their income.

When to File Form 1120

Filing Deadlines

Corporations must file their income tax return by the 15th day of the 4th month after the end of their tax year. New corporations filing short-period returns must follow the same deadline. If the fiscal year ends on June 30, the deadline is the 15th day of the 3rd month after the tax year ends.



If a corporation cannot meet the deadline, they can apply for an automatic extension using Form 7004. It’s important to apply before the deadline to get approval for the extension.

How to File Form 1120

Completing the Form

To file Form 1120, corporations must:

  1. Download and fill in the form with accurate information.
  2. Report income, deductions, and losses.
  3. Sign and date the form by an authorized person (e.g., president, treasurer).

Filing Methods

Corporations can file Form 1120 either by paper return or electronically. Ensure all applicable schedules are attached in the correct order for efficient processing.

Key Sections of Form 1120

  • First Page: Includes income, deductions, and tax, payments, and refundable credits.
  • Second Page: Contains Schedule C.
  • Third Page: Contains Schedule J.
  • Fourth and Fifth Pages: Contain Schedule K.
  • Sixth Page: Contains Schedules L, M-1, and M-2.

Corporations should carefully read the instructions provided with the form to ensure accurate completion.


Filing Form 1120 is crucial for corporations to comply with IRS regulations. This form helps report income and calculate tax liabilities accurately. By following the steps outlined in this guide, corporations can ensure they file their tax returns correctly and on time, avoiding any penalties or issues.



What is Form 1120?

Form 1120 is the U.S. Corporation Income Tax Return used by corporations to report income, losses, and deductions.


Who needs to file Form 1120?

All domestic corporations, unless exempt, must file Form 1120 to report their income and calculate tax liability.

How do I download Form 1120?

Visit the IRS website, click on “Forms and Instructions,” search for “Form 1120,” and download it.


When is the deadline to file Form 1120?

Corporations must file by the 15th day of the 4th month after the end of their tax year. New corporations follow the same deadline for short-period returns.


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By Arnia
A Certified Public Accountant specializing in personal finance and taxation. Arnia engaging writing style and deep understanding of tax codes make her articles a must-read for individuals seeking to maximize their tax savings.
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