When Do Corporate Taxes Need to Be Filed?

Corporate tax filing is an obligation for businesses operating in the United States. It involves adhering to specific deadlines and reporting financial information to the Internal Revenue Service (IRS). Understanding these requirements is important for maintaining compliance and ensuring the financial health of a corporation. This process helps the government collect revenue and provides transparency regarding corporate financial activities.

Key Corporate Tax Deadlines

Federal income tax filing deadlines for corporations vary by entity type and tax year. C-corporations, which file Form 1120, have a deadline of the 15th day of the fourth month following the close of their tax year. For calendar-year C-corps, this means April 15. However, C-corps with a fiscal year ending on June 30 file by the 15th day of the third month for tax years beginning before 2026, and by the 15th day of the fourth month for tax years beginning after 2025. If a C-corp operates on a fiscal year ending, for example, on March 31, its tax return is due by July 15.

S-corporations, which file Form 1120-S, face an earlier deadline. Their tax returns are due on the 15th day of the third month following the close of their tax year. For calendar-year S-corps, this means March 15. If March 15 falls on a weekend or holiday, the deadline shifts to the next business day, such as March 17 in 2025. For an S-corp with a fiscal year ending, for instance, on January 31, the due date is April 15. If an S-corp’s fiscal year ends on June 30, its deadline is September 15.

Requesting a Filing Extension

Businesses unable to meet their original tax filing deadline can request an extension by filing Form 7004. This form provides an automatic six-month extension for filing the corporate tax return. For calendar-year C-corps, an extension moves their filing deadline from April 15 to October 15. For calendar-year S-corps, the extension shifts the deadline from March 15 to September 15.

An extension of time to file does not extend the time to pay any taxes due. Estimated tax payments are still required by the original deadline to avoid penalties and interest. Businesses should estimate their tax liability and pay that amount when filing Form 7004. Failure to pay by the original due date, even with an approved extension to file, can result in penalties.

Gathering Information for Filing

Preparing a corporate tax return requires a compilation of financial information and documents. Key financial statements, such as income statements and balance sheets, are important. Businesses also need their general ledger, payroll records, and depreciation schedules. Prior year tax returns are useful for reference.

For C-corporations, the main form is Form 1120, “U.S. Corporation Income Tax Return.” S-corporations use Form 1120-S, “U.S. Income Tax Return for an S Corporation.” These forms require detailed information about a corporation’s financial activities, including gross receipts or sales, cost of goods sold, and various operating expenses.

Deductions and credits must also be accurately calculated and reported. For S-corporations, shareholder information, including ownership percentages and allocations of income, deductions, and credits, is necessary for Schedule K and Schedule K-1. Schedule K-1s are then provided to individual shareholders for their personal tax returns. Official forms and their instructions are available directly from the IRS website.

Submitting Your Corporate Tax Return

Once the corporate tax return is completed, there are several submission methods. Most businesses choose to e-file their returns through IRS-authorized tax software or tax professionals. This electronic method is the preferred way to submit returns.

Alternatively, businesses can mail a paper return to the IRS. The specific mailing address depends on the type of form being filed and the corporation’s location or asset size. For example, some Form 1120 returns with total assets less than $10 million are mailed to an address in Kansas City, MO. Other forms or larger corporations may have different designated mailing addresses, which are found in the form instructions.

Tax payments can also be made through various channels. The Electronic Federal Tax Payment System (EFTPS) is a common method for electronic payments. Other options include direct debit from a bank account when e-filing, or sending a check or money order with a paper return.

Penalties for Missing Deadlines

Failing to meet corporate tax deadlines can result in penalties and interest charges. The IRS imposes penalties for failure to file on time and for failure to pay on time. The penalty for failure to file is 5% of the unpaid tax for each month or part of a month the return is late, up to a maximum of 25% of the unpaid tax. If the return is more than 60 days late, a minimum penalty may apply, which for 2025 is the lesser of $510 or 100% of the unpaid tax.

The penalty for failure to pay is 0.5% of the unpaid taxes for each month or part of a month the taxes remain unpaid, also capped at 25% of the unpaid tax. Interest also accrues on any underpaid tax amount, beginning from the original due date. These interest rates are adjusted quarterly. Even if an extension to file was granted, penalties and interest can still apply if the tax due was not paid by the original deadline.