Your income tax return is due on April 15th. If you can't finish it by then, don't panic. You can get an automatic extension of time to file your return until October 15th.
However, obtaining an extension of time to file your return does not extend the time you have to pay any taxes you owe the IRS. Your tax payments (if any) are still due on April 15th. So, if you do owe the IRS money, you'll need to estimate out how much and pay the amount before April 15th. If you pay late, you'll be charged interest and possibly penalties as well. You can get a free estimate of how much tax you owe by using TurboTax’s TaxCaster or H&R Block's Tax Calculator.
Obtaining an extension is easy. All you have to do is file IRS Form 4868, Application For Automatic Extension of Time To File U.S. Individual Tax Return--a simple form that should take you less than one minute to complete. You don't have to tell the IRS why you want an extension--you get it automatically by timely filing the form.
You can send in Form 4868 to the IRS electronically with tax software such as Turbotax or H&R Block, or you have your tax preparer do it for you. However, it's easier just to complete the form online, print it out, and postal mail it to the IRS along with a check or money order for any tax you owe. Your extension letter must be postmarked by April 15th; it doesn't matter if it's received by the IRS after that date.
If you live in one of the 43 states that has income taxes, you'll need to file an extension to file your state tax return. Each state has its own procedure for getting an extension. However, many states allow you to get an automatic extension using a procedure similar to that of the IRS. For information, visit your state income tax agency's websites. To find your state's website, you can use the Federation of Tax Administrators' Links to State Websites.