DOR Taxation web site


The Colorado taxable income is then taxed at a flat rate of 4.63%.

Filing Tips

  • File the 112 corporation form through Revenue Online.
  • Be sure to attach schedules. Upload the schedules through Revenue Online.
    For example, if a corporation is apportioning income, the taxpayer must attach an accurately completed SF apportionment schedule or else the apportionment election will be disallowed. 
     Additionally, they should select correct apportionment methods. For example, the gross Colorado sales apportionment method should not be selected if the corporation is electing to be taxed on its Colorado taxable income. See Income Tax Common Filing Errors for addtional filing tips.
  • Returns are due on the 15th day of the fourth month following the close of the taxable year. A corporation is granted an automatic six-month extension of time for filing. If either of these dates fall on a weekend or holiday, the tax should be filed by the next business day.


Corporations that are members of an affiliated group of corporations, as defined in section 1504 of the federal Internal Revenue Code, must determine whether to file separate returns, a consolidated return, a combined return, or a combined/consolidated return. Please see Publication FYI Income 60, Combined and Consolidated Corporation Returns.

A Corporation doing business only in Colorado will compute its tax on 100% of the Colorado taxable income. However, a corporation doing business in more than one state must apportion its taxable income to any states in which the corporation is doing business.