Colorado

Calendar year Colorado business tax returns are due by April 15th. Non calendar year returns are due within 3½ months following the end of the tax year. If you cannot file by then, you can get an automatic 6-month state tax extension (which moves the deadline to October 15 for calendar year filers).

A Colorado tax extension does NOT grant you more time to pay your state tax. To avoid incurring late payment penalties, 90% of your net tax liability must be paid by the original deadline of your return. If no tax payment is due, no form or application for an automatic extension is required.

Corporations

To make a state tax payment by mail, use Colorado Form 0158-C (Extension of Time for Filing a Colorado C Corporation Income Tax Return). Note that Form 0158-C should only be used if you are not paying online.

S Corporations and Partnerships

To make a state tax payment by mail, use Colorado Form 0158-N (Automatic Filing Extension). Note that Form 0158-N should only be used if you are not paying online.

To make your state tax payment online, go to the Colorado “Revenue Online” website

For more information, visit the Colorado DOR Division of Taxation website.

Colorado Taxpayer information and assistance: (303)238-7378