Colorado Filing Due Date: Businesses must file their Colorado tax return by April 15 — or within 3½ months following the close of the taxable year (for fiscal year filers).
Extended Deadline with Colorado Tax Extension: Colorado offers a 6-month extension, which moves the filing deadline to October 15 (for calendar year taxpayers).
Colorado Tax Extension Form: Colorado’s tax extension is automatic, which means there is no application to submit unless you have tax liability.
Colorado Extension Payment Requirement: An extension of time to file is not an extension of time to pay. If you owe Colorado tax, at least 90% of your net tax liability must be paid by the original due date, or penalties and interest will apply.
C corporations can make an extension payment using Colorado Form 0158-C. S corporations and partnerships can make a Colorado extension payment using Form 0158-N. Extension payments can also be made electronically via the “Revenue Online” system.
Colorado Tax Extension Tip: If your Colorado tax liability is zero, you do not need to file anything to get a state extension.