Your chosen tax year dates are normally Jan-Dec unless you specific asked for it to be something else in your EIN application (SS-4). - for example Apr-Mar is common for those with Indian subsidiaries to match the underlying India tax year. You can check your chosen US dates in your SS-4 (field 12)or your EIN issuance letter (paragraph 3). Depending on your chosen tax year dates, and only if you want a 6-month extension to your corporate tax deadline, you will need to file the Form 7004 either by 15th April (if your tax year is Jan-Dec) or 15th Jul (if your tax year is Mar-Apr). This buys you a 6 month breather.

Suppose you fail to file a 7004 tax extension or tax return within the appropriate deadline (March 15, 2023, for S-corporations and partnerships and April 18, 2023, for corporations and other businesses). In that case, the IRS will charge interest and penalties on any unpaid Federal taxes.

If you do not file and owe taxes, the failure-to-file penalty is 5% per month (up to 5 months) of the amount due. If your return is over 60 days late, you may be subject to a $135 minimum penalty. The IRS will also impose a failure-to-pay penalty of 0.5% per month (up to 25%) of the amount due if you file a return or extension but don’t pay all your taxes on time.

C Corporations must file Form 7004 on or before the original deadline of their tax return Form 1120, which is by the 15th day of the 4th month after the taxable year ends.

The deadline for C-Corporations following the calendar tax year is April 18, 2023.