Form 1120: Reporting how much tax your C Corp or LLC owes

Business tax forms can get confusing. “What business entity files what?” you may wonder.

Well, whether you are a newly formed C corporation vs. an LLC (taxed as a corporation), you will definitely want to take note of Form 1120. Why’s that? Ultimately, this form will tell you how much business tax you owe for the year.

Form 1120

Form 1120 is the U.S. corporation income tax return and should be filed yearly.

In what situations should you use 1120 tax Form?

The 1120 tax form is used to:

  • Report income, gains, losses, deductions, and credits
  • Figure out income tax liability

Who should use IRS Form 1120?

Domestic C corporations and LLCs who elect to be taxed as a corporation use IRS form 1120. S corporations file the 1120-S tax form instead.

What information does the Form 1120 include?

On Form 1120, you’ll need to include:

  • Business name
  • Physical address
  • Federal Employer Identification Number (EIN/FEIN)
  • Date of incorporation
  • Total assets

Income details, like gross receipt amount, cost of goods sold, interest, dividends, royalties, rent, and capital gain. Form 1120 contains several schedules and may also require you to file additional forms include Form 8949 and Form 3800.

It’s not necessary to attach proof of tax deductions, but you should keep the necessary documentation on file.

When is Form 1120 due?

Corporations using a calendar basis tax year, i.e., year beginning on January 1 and year-ending on December 31, should file Form 1120 by April 15 of the following year. The form is due the next business day if the date falls on a weekend or holiday.

If your business doesn’t adhere to a Jan. 1 to Dec. 31 tax year, Form 1120 must be filed by the 15th day of the fourth month after the end of your business’s tax year. However, if your fiscal tax year ends June 30, the Form 1120 must be filed by the 15th day of the third month after the end of its tax year, which usually falls on September 15.

For returns due after 2019, the minimum penalty for failure to file a return that is more than 60 days late has increased to the smaller of the tax due or $435, according to the IRS instructions for Form 1120.

Where can you find the 1120 tax form?

If you prepare your own corporate tax return, you can use the IRS website’s interactive version of the 1120 tax form. You can complete it online, download it, or print it off, and attach the additional forms and schedules to Form 1120, if you paper-filed. View a list of IRS addresses here.

Sound complicated? We get it, you’d probably rather get back to the business of making your company thrive instead of working through Form 1120.

Let us dive into the details. When you work with Block Advisors, we’ll complete the form for you. In fact, this may be one of multiple business tax forms and schedules your tax pro will assist you with.

Where to go for more tax help?

Rely on our team of small business certified tax pros to get your taxes right and keep your business on track. Connect with us at


Find tax help in your area.