Colorado extension of time to file still means tax is due in April

STATEWIDE — Taxpayers who cannot file their 2017 Colorado income tax return by the April 17 deadline may take advantage of the state’s automatic six-month extension of time to file. Taxpayers do not need to notify the Colorado Department of Revenue (CDOR) if they decide to take the filing extension. 

There is no extension for paying the tax due, though. Taxpayers who owe state income tax must pay at least 90 percent of the tax liability by Tuesday, April 17 to avoid penalties. As long as the return and balance owed are sent to CDOR by the October 15 extension deadline, any remaining balance is subject to interest only. Those who pay less than the required 90 percent of the amount due by the April deadline will be charged interest and penalty on the unpaid balance.

Taxpayers can use Revenue Online, CDOR’s free, one-stop website for filing taxes and managing accounts at, to calculate the total tax owed, plus interest and penalty. Alternatively, they may choose to manually calculate penalty and interest using the instructions in the 2017 Colorado Individual Income Tax Form 104 booklet for lines 32 and 33, respectively.

There are two payment options for taxpayers – via credit card or e-check on Revenue Online or mail. No Login ID is required to make a payment on Revenue Online. Taxpayers can click on “Make a Payment” in the Quick Links section and then simply enter all the relevant payment information. A few quick steps and your payment is on its way! Mailed payments should be sent with the form DR 0158-I: Extension Payment for Colorado Individual Income Tax to:

       Colorado Department of Revenue

       Denver, CO 80261-0008

This mailing address and ZIP Code are exclusive to CDOR, so a street address is not required. To ensure a mailed payment is credited to the correct account, taxpayers should include their Social Security number(s) and “2017 DR 0158-I” on the check or money order.

2017 income tax return filing deadlines:

• April 17, 2018: Federal and State income tax returns are due. 90% of Colorado tax liability due.

• October 15, 2018: Automatic extension deadline for Colorado income tax returns if not filed by the April deadline. Payments for total 2017 Colorado income taxes, including applicable penalty and interest, are due.


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