For Late Filers

If you're reading this between late April and December, and you didn't file your prior year's taxes, you're going to owe a lot in penalties. However, it's better to pay as soon as possible, even if you didn't file for an extension, becuase those fees (plus interest) add up for every year you don't pay. And, remember what happened to Al Capone: The IRS has a long memory, and ways of tracking you down.

If you're reading this early in the year, even April 14 or 15, read on.

If you think you can't finish your tax calculations in time to file -- whether it's because you're missing some paperwork or simply procrastinated -- you can apply for an automatic four-month extension with Form 4868. (You're supposed to get that in by the filing deadline, but if you're a day or so late it's not likely you'll be penalized.)

The extension granted applies to filing your taxes, though, not for paying them; you must make a good faith estimate of your liability. If you don't, the extension will still be allowed, but you'll be subject to interest charges and possible penalties. Also, the Internal Revenue Service will fine you an additional late-payment penalty if the check you send with Form 4868, plus whatever tax you paid throughout the year, still amounts to less than 90 percent of the total amount due for the year -- unless you can show reasonable cause for the delinquency.

You can skip Form 4868 and get an extension by phone (888-272-9829) if you charge your tax payment on a credit card (American Express, MasterCard or Discover).

If paying your tax would cause a severe hardship, you can apply for a special payment extension on Form 1127. This extension is generally limited to six months, and you'll owe interest on the late payment.