In order to avoid penalties and interest, submit an extension of time to file request (Form FR-127 ) on or before April 15.
Remember that any tax due must be paid in full with the extension request. Penalties and interest will be calculated on any tax outstanding from the time that the return is due until the tax is paid, even if an extension is granted (In other words, there is no extension for payments that you owe, just for the actual filing of your return). A copy of the federal extension request is NOT acceptable for requesting an extension of time for filing a DC return.
By filing a timely Form FR-127, plus any payment due, you will have a 6-month extension to file your return. The return will then be due on October 15.
If you are living or traveling outside of the U.S., you may receive another 6-month extension, but you must file for the first 6-month extension by April 15 before applying for the additional extension of time to file. The tax due must still be paid in full with the first extension request.
The Office of Tax and Revenue will grant members of the US Armed Forces who serve in designated Combat Zones an extension of up to an additional 6 months to file their District income taxes, as well as pay any amounts that are due.
During this period of extension, assessment and collection deadlines are extended and no penalty and interest will be charged. The extension also applies to spouses, whether they file joint or separate returns.