Apr. 18 is the 2017 Income Tax Filing Deadline

The filing due date for Colorado income tax returns due in 2017 is Tuesday, April 18, 2017 rather than April 15.
In some years, the District of Columbia’s observance of Emancipation Day can affect the nation’s filing deadline. 
Returns filed on Tuesday, April 18 will be considered as timely filed. Revenue Online will accept returns as timely filed until midnight. Returns that are mailed must be postmarked by April 18. An automatic extension to file is granted until Monday, October 16, 2017 but there is no extension to pay. See page 17 of the 104 Booklet for more information on extensions.
Filing Options:
  • Revenue Online: You may use the Colorado Department of Revenue’s free e-file and account service Revenue Online to file your state income tax. You do not need to login to Revenue Online to file a return. After you file, you have the option of setting up a Login ID and Password to view your income tax account in Revenue Online. Note: If you are a first-time filer, you cannot use Revenue Online. You must either submit a paper return or use a third-party software to file electronically. You may use Revenue Online after you’ve filed your first tax return with the Department.
  • You may opt to e-file through a paid tax professional or purchase tax software to complete and file returns. 
  • On paper using the 104 Booklet

Expect to get a refund this year but can't make the deadline?
If you can’t file your Colorado income tax return by the deadline of Tuesday, April 18, 2017, you may take advantage of the state’s automatic six-month extension of time to file. There is no form to fill out to notify the Department of Revenue that you are taking the extension, however there is no extension for tax due. The extension applies to filing Colorado income tax information, either on paper or electronically, not to any state income tax you may owe. If you expect to get a refund this year but do not make the filing deadline, you can still file your state income tax on or before Monday, October 16.

Owe state income tax?
90 percent of the tax liability must be paid on or before Tuesday, April 18 to avoid penalties. Any remaining balance due would be subject to interest only. If you owe tax, you must either pay through Revenue Online or submit your payment with the Extension Payment Voucher (DR 158-I). To ensure a mailed payment is credited to the correct account, taxpayers should include their Social Security number(s) and “2016 DR 0158-I” on the check or money order.