If you filed a federal extension on or before the April 18 tax deadline, but your extension got rejected, you have until April 23 to either resubmit or mail your extension.
To mail your extension, you can download and print Form 4868, complete it, and get it postmarked before 11:59 p.m. on April 23. Payment and mailing instructions are on pages 3 and 4 of your printout.
If you owe, you can get an extension by paying all or part of your estimated federal income tax due. Just make sure to choose Extension as your reason for payment. This lets you avoid having to file a separate form and you'll get a confirmation number for your records.
Keep in mind that if you have a refund coming from the IRS, there's no penalty for failing to file your tax return by the deadline, even if you don't ask for an extension.
