How Filing Tax Extensions Works

A long line at a Chicago post office on April 15, 2004.
A long line at a Chicago post office on April 15, 2004.
Tim Boyle/Getty Images

­April 15: A day of dread.

People rush to complete their forms and race to the post office to mail their forms, only to discover that a long line awaits them. If you get your envelope postmarked before midnight, you're in the clear, nothing to worry about.

But what if you didn't beat the deadline? What if you forgot to file? Or what if you couldn't file because you didn't have all the necessary information to fill out your Form 1040? Even worse, what if you owe thousands of dollars more than you thought you would, because you claimed too many exemptions on your W-4, and there is just no way you can pay it all right now?

Luckily -- or unluckily, in some cases -- the IRS has seen every one of these situations and can tell you what to do about it.

There are many solutions to these problems, and this article will explain how to file for a filing extension and an installment agreement. We'll also discuss the consequences of paying late: penalties and interest.

First, we'll take a look at how to file for a federal income tax filing extension. Read all about it on the next page.