How to file a tax extension, no matter how disorganized you are

It's inevitable: You're fairly sure you're going to have all your tax documentation together, and then something goes awry. You don't receive all your tax forms, you've misplaced a receipt, or you're otherwise unable to file your return by the due date.

If you need more time to prepare your federal tax return, you'll need to file an extension.

To get started, you need the following information:

1. Your personal details, including your Social Security number, address, and the name and taxpayer ID number of your spouse.
2. A copy of your 2008 tax return.
3. A list of tax payments made in 2008.

If your tax situation hasn't changed since last year, you can use your 2008 tax return to estimate your tax liability. You'll find your total tax liability from 2008 on line 60 for the form 1040, line 37 for form 1040A, and line 11 for form 1040EZ. Subtract any payments you've made throughout the year and report your balance due on line 6 of the extension form. Ideally, if you owe a balance, you'll pay at least that much along with your extension to avoid a potential penalty.

To prepare and file the extension for your federal income tax return, you'll need to select a method:

File a paper extension. Most taxpayers are eligible for an automatic 6-month extension of time to file. To get the extension, you must file Form 4868, Application for Automatic Extension of Time To File U.S. Income Tax Return (downloadable here), by April 15. Assuming you file on time, you'll be extended through Oct. 15. A longer extension may be granted if you're living out of the country.

File online. You can apply for an extension by filing form 4868 online through a software preparation service like TurboTax or by hiring a tax professional who uses e-file. If you want to make a payment with your online filing, you can pay by electronic funds withdrawal or send a check to the IRS. As with a paper return, the extension must be filed before the end of day on April 15.

Pay by credit card. You can also apply for an extension by paying part or all of your estimate of income tax due by using a credit or debit card. To pay by credit or debit card, call toll-free or visit the Web site of one of the following service providers approved by the IRS:

No matter which option you choose, remember that an extension must be filed in a timely manner. More important, filing an extension extends the time to file but not the time to pay. As with the form, payments should be made by April 15.

If you run into difficulty or need more information, the IRS can help. You can call 1-800-829-1040 for assistance, Monday through Friday, from 7 a.m.–10 p.m. your local time (Alaska & Hawaii follow Pacific Time).

Note: This article was originally published on January 20, 2010.