IRS Form 1120 (US Corporate Income Tax Return) is filed by C corporations to report their income, gains, losses, deductions, and credits, and to calculate its income tax liability.

A C corporation is a taxable entity, not to be confused with an S corporation, a pass-through entity that must file Form 1120-S (US Income Tax Return for an S Corporation).

Purpose of Form 1120
  • Income Reporting. To report the corporation’s income, expenses, gains, losses, credits, and other transactions.
  • Tax Calculation. Corporations are generally subject to a 21% tax rate on its net taxable income. A corporation’s net taxable income may be different from its net income per books. Any book-to-tax adjustments are reported on Schedule M-1.
Who Must File
  • C Corporations. Domestic corporations must file Form 1120 annually. This includes LLCs that elected to be taxed as a C corporation by filing Form 8832 (Entity Classification Election).
  • Due Date. Form 1120 must be filed annually and is due on or before the 15th day of the 4th month following the close of the corporation’s tax year. For a calendar year corporation, the due date is generally April 15. Extensions can be requested by filing Form 7004 (Application for Extension of Time to File).
Information Required on Form 1120
  • Basic Information. Name of corporation, address, Employer Identification Number (EIN), and the date of incorporation.
  • Income and Deductions. The corporation must report the gross amounts of income, deductions, credits, and any estimated tax payments made during the year.
  • Basic Schedules. The standard Form 1120 comprises six pages and includes Schedules C, J, K, L, M-1, and M-2.
  • Additional Schedules. Depending on the corporation’s activities, it may need to include additional forms, schedules, and attachments. For example, if the corporation sells inventoried products, it should include Form 1125-A (Cost of Goods Sold).
Video Tutorials on Form 1120

Please visit our channel for video tutorials on how to prepare Form 1120 for various scenarios:

Additional Information

Corporations can find more information in the Form 1120 Instructions and IRS Publication 542 (Corporations).