Filing Due Date
Tuesday, April 18, 2023
If you cannot file your Colorado income tax return by the deadline, 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.
If you owe Colorado state income tax, 90% of the tax liability must be paid by April 18th to avoid penalties. Any remaining balance due would be subject to interest only. You need to either pay through Revenue Online or submit your payment with the Extension Payment Form (DR 0158-I). Once you have paid at least 90% of your income tax liability by April 18th, you will have until October 15th to file your Colorado Income Tax Return (DR 0104).
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 October 17th.