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Income Tax | Corporation -- File
First, complete the federal income tax return you will file with the Internal Revenue Service (IRS). You will use figures or data from your federal return on your Colorado income tax return.
The Colorado Department of Revenue offers a free e-file and account service called
to file your state income tax. However, if you are a first-time Colorado income tax filer, you must file a paper return so that the department can assign a Colorado Account Number (CAN) to you. After the first return is filed, you may create your own User ID and Password to use in Revenue Online (with the CAN assigned by the department) to e-file future returns free of charge from within your Colorado tax account, and to review your tax account history.
See Quick Answers,
Sign up for Revenue Online account access
Current Income Tax E-Filers Handbook
Current Income Tax Accepted Software
Instructions and Forms
Credit Schedule for Corporations (112CR)
and the corporation income tax instructions booklet.
For information on subtractions, please see
FYI Income 58
Disposition of Assets
Excess Oil Shale Depletion
Foreign Source Income
Income/Gain Previously Taxed
Qualified Sales Under Threat of Condemnation
Ridesharing or Mass Transit
Section 78 Dividend Gross-Up
Best Practices/Common Errors
Tax Year 2016
Current Year Income Tax Forms
Corporation Current Year
Prior Year Income Tax Forms
Corporation Prior Year
Instructions for Substitute FORM Developers
Substitute Form Developers website
Instructions for Tax SOFTWARE Developers
Software Developers -- Income Tax
Corporate income tax returns are due 3½ months after the end of your tax year, or by Tuesday, April 18, 2017 for traditional calendar year filers. See the
Emancipation Day webpage
for more information tax due date.
If you are unable to file by your prescribed due date, you may file under extension. This will allow you an additional six months to file your return, or until Monday, October 16, 2017 for traditional calendar year filers. However, the extension to file does not allow you to extend your payment due date. You must pay at least 90% of your tax liability by the original due date of your return and the remainder by the filing extension due date to avoid delinquent payment penalties.
See Quick Answers,
Amending a Return
Federal Tax Information
Colorado state income tax is different from federal income tax. You must determine your federal income tax by preparing your federal return first. Then you can complete the Colorado return. For information on how to file your federal return, including links to services where you can file both federal and state returns free of charge, see the
Internal Revenue Service website
Disagree with a Billing Notice
Taxpayers who disagree with the balance due notice have the right to protest the amount due. The protest must be filed within 30 days from the date of the notice. Refer to your correspondence for any specific documentation required.
File a Protest
On the web through
, click on the File a Protest link. It is not necessary to Login to Revenue Online to file a protest. Supporting documentation may also be attached to the protest in Revenue Online.
Colorado Department of Revenue
Protest Section #240
PO BOX 17087
Denver, CO 80217-0087