Dates and deadlines related to the filing of income tax returns this year:
April 15: File your tax return by this deadline or use Form 4868 to ask the IRS for an automatic four-month extension. The extension gives taxpayers more time for paperwork, but it doesn't change the April 15 tax payment deadline. The IRS asks that you estimate taxes due on the extension form. Interest and late payment penalties may be charged on taxes left unpaid after April 15.
Aug. 15: File your tax return if you have asked for an extension. In special cases, the IRS lets taxpayers who need still more time apply for another two months. The instructions accompanying Form 2688, used to apply for the extra two months of time, says taxpayers must provide "a good reason why the first four months were not enough."
OCT. 17: File your tax return if you have been granted an extra two-month extension. (The traditional Oct. 15 deadline falls on a Saturday this year, giving taxpayers an extra weekend to make the final deadline.)