Fill Out IRS Form 1120 Online
U.S. Corporation Income Tax Return
Internal Revenue Service
The annual federal income tax return filed by C corporations.
Reviewed July 2026
How it works
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IRS Form 1120, U.S. Corporation Income Tax Return, is the annual return domestic C corporations file to report income, gains, losses, deductions, and credits, and to figure their federal income tax liability. Unlike partnerships and S corporations, a C corporation pays tax at the entity level.
You can fill out Form 1120 in the Universal PDF editor, complete the income and deduction lines along with the required schedules, and download the finished PDF for your records or for review with your tax adviser.
What is Form 1120 used for
Form 1120 is the C corporation's core tax filing. It computes taxable income from gross receipts and other income minus business deductions, applies the corporate tax rate, and reconciles payments and credits to determine the balance due or overpayment.
The form carries a set of built-in schedules, including Schedule C for dividends and special deductions, Schedule J for tax computation and payments, Schedule K for other information, Schedule L for the balance sheet, and Schedules M-1 and M-2 for reconciling book and tax income and retained earnings.
Who files Form 1120
The filers are mostly domestic corporations that have not elected S status, plus some entities in special situations:
- Domestic C corporations, regardless of whether they had taxable income for the year.
- LLCs that elected to be taxed as C corporations on Form 8832.
- Corporations in bankruptcy, which still must file.
- Certain specialized corporations file 1120 variants instead, such as Form 1120-S for S corporations.
How to fill out Form 1120
Page 1 begins with identifying information, then income lines (gross receipts, cost of goods sold, gross profit, dividends, interest, rents, and other income) followed by deduction lines (salaries, repairs, rents, taxes, interest, depreciation, advertising, and more) down to taxable income and total tax.
Work through the supporting schedules in order, then attach any additional forms the return triggers, such as depreciation or credit forms. Corporations with larger balance sheets face extra reconciliation reporting, and most corporations now file electronically through approved software, so a completed PDF often serves as the working copy and record.
Deadlines and extensions
Form 1120 is generally due by the 15th day of the fourth month after the end of the corporation's tax year, which is April 15 for calendar-year corporations. A corporation with a fiscal year ending June 30 has a different statutory due date, so fiscal-year filers should check the current instructions.
Form 7004 provides an automatic six-month extension of time to file, though it does not extend the time to pay tax owed. Estimated tax payments during the year follow their own quarterly schedule.
Frequently asked questions
Generally the 15th day of the fourth month after the tax year ends, April 15 for calendar-year corporations. Form 7004 grants an automatic six-month filing extension.
Yes. A domestic corporation must file every year it exists, even with no taxable income, until it is formally dissolved.
Form 1120 is for C corporations, which pay tax at the corporate level. Form 1120-S is for S corporations, which pass income through to shareholders.
Yes, if it elected corporate taxation on Form 8832. Without that election, a multi-member LLC files Form 1065 and a single-member LLC reports on its owner's return.
No. Form 7004 extends the time to file the return, but the tax is still due by the original deadline, and interest applies to late payments.
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