When Is Corporation Tax Due? Filing & Payment Deadlines

Understanding corporate tax obligations and their associated deadlines is essential for businesses. Adhering to these schedules ensures compliance with federal tax laws, preventing potential penalties and interest charges. Businesses must track due dates for annual tax returns and estimated tax payments to maintain financial standing.

Understanding Annual Filing Deadlines

The federal income tax return deadline for corporations varies depending on the type of corporation and its fiscal year.
For C corporations, which file Form 1120, the income tax return is generally due by the 15th day of the fourth month following the close of their tax year. For calendar-year C corporations, this typically means an April 15 deadline. This date also generally marks the deadline for paying any tax due.

S corporations, which file Form 1120-S, have a slightly earlier deadline for their annual return. Their federal income tax return is due by the 15th day of the third month after the end of their tax year. For calendar-year S corporations, this translates to a March 15 deadline. S corporations are generally “pass-through” entities, meaning income and losses are reported on shareholders’ personal tax returns, and the corporation itself typically does not pay income tax at the corporate level.

For corporations operating on a fiscal year that does not align with the calendar year, these deadlines adjust accordingly. A C corporation’s Form 1120 is due on the 15th day of the fourth month after its fiscal year ends. An S corporation’s Form 1120-S is due on the 15th day of the third month following its fiscal year end. For example, a C corporation with a fiscal year ending October 31 would have a February 15 due date for its return.

There is a specific exception for C corporations with a fiscal year ending on June 30. For these entities, the Form 1120 is due by the 15th day of the third month after the close of their tax year, which is September 15. This aligns their filing deadline with that of S corporations, despite being C corporations. If a due date falls on a weekend or legal holiday, the deadline shifts to the next business day.

Quarterly Estimated Tax Deadlines

Corporations generally have an obligation to pay estimated income tax throughout their tax year if they anticipate owing a certain amount of tax. For C corporations, estimated taxes are typically required if the corporation expects its tax liability to be $500 or more for the year. These payments ensure that tax liabilities are remitted throughout the year rather than in one lump sum at year-end.

For calendar-year C corporations, federal quarterly estimated tax payments are due on specific dates: April 15 for the first quarter, June 15 for the second quarter, September 15 for the third quarter, and December 15 for the fourth quarter. These payments help corporations avoid underpayment penalties.

Fiscal year corporations also make four estimated tax payments, but their due dates are adjusted to align with their specific tax year. These payments are generally due on the 15th day of the fourth, sixth, ninth, and twelfth months of their tax year. The calculation of these estimated payments can be facilitated by using Form 1120-W, U.S. Corporation Estimated Tax, which is a worksheet designed to help determine the required installments.

Form 1120-W is a worksheet for internal use and is not filed with the IRS. Its purpose is to guide the corporation in calculating the correct amount of estimated tax to pay. S corporations generally do not pay estimated income tax at the corporate level because their income passes through to shareholders, who then report it on their individual tax returns and may need to pay individual estimated taxes.

Requesting a Filing Extension

If a corporation needs additional time to prepare and file its annual income tax return, it can request an extension from the IRS. This involves filing Form 7004, Application for Automatic Extension of Time To File Certain Business Income Tax, Information, and Other Returns. This form must be submitted by the original due date of the corporation’s tax return.

An approved Form 7004 grants an automatic six-month extension to file the return. For calendar-year C corporations, an extension moves their filing deadline from April 15 to October 15. For calendar-year S corporations, an extension shifts their filing deadline from March 15 to September 15.

An extension of time to file is not an extension of time to pay any tax owed. The corporation must still estimate its tax liability and pay any anticipated tax by the original due date to avoid potential penalties and interest. Failure to pay by the original deadline, even with an extension to file, can result in interest accruing on the unpaid amount and late payment penalties.

For fiscal year corporations, the extended due date will be six months after their original filing deadline. For example, a C corporation with a June 30 fiscal year end, whose original due date is September 15, would have an extended deadline of April 15 of the following year. Filing Form 7004 electronically is recommended for faster processing and confirmation.