Filing Deadline

• Taxes must be filed with the IRS or received by the post office by April 15 in most years. When April 15 falls on a weekend or on Emancipation Day, which is observed in the District of Columbia, returns are due the first weekday following the holiday or weekend. Because Emancipation Day falls on April 15, a Friday, in 2011, your taxes must be filed by April 18. To meet deadline requirements, you must electronically file by midnight April 18 or mail your tax documents, properly addressed and with correct postage, by the close of the April 18 postal day. If your taxes are postmarked by April 18, 2011, it doesn't matter when the IRS actually receives the documents.
  
  

Automatic Extensions

• If you anticipate being unable to file by the deadline, you may file for an automatic extension using Form 4868. When filed, this grants taxpayers an automatic six-month extension to file their taxes, making them due Oct. 15, or, in 2011, on Oct. 17. If you file for an automatic extension and pay at least 90 percent of your estimated tax bill, you won't incur a late-filing penalty or late payment charges. If you expect to have any taxes due, you must pay at least $1 when filing a Form 4868.
  
  

Penalties

• If you file late and fail to file an extension or don't pay an appropriate portion of your tax bill with your extension, you'll face additional charges for your tardiness. The IRS sticks you with two types of charges, a late filing penalty and a late payment penalty. For filing late, you'll be assessed an additional 5 percent of your tax bill for each calendar month that the return is delayed, with a maximum fine of 25 percent. On top of late filing charges, you'll also face a 0.5 percent per month charge assessed against your tax bill. Late payment charges cap at a 25 percent penalty.
  
  

Owed a Refund

• If you expect to receive a refund from the IRS, you're granted amnesty through the penalty calculation methods the IRS uses. Because late payment fees are based upon your total tax bill, filers who receive a refund have no tax basis for which to base the penalties. Because of this, if you stand to receive a refund, you can file late without incurring tax penalties. If your return is processed 45 days late for whatever reason, including late filing, your return amount begins accruing interest charges and your refund grows accordingly.