Colorado Flag Picture

Colorado Tax Resources

Income Tax Rate: 4.63% Flat (Colorado has a Flat Income Tax Rate)
Governor: Bill Ritter
Income Tax Revenue (2007): $9,205,912,000.00
Colorado Population 4,842,770

Colorado Department of Revenue
1375 Sherman St.
Denver, CO 80261

Phone Number: (303) 238-7378

Colorado Mailing Address

Wondering where to mail your Colorado taxes? Here's the address:

Colorado Department of Revenue
Denver, CO 80261-0005



Colorado Tax Filing Guide

Here are detailed instructions for filing taxes in the state of Colorado.

Colorado Residents

If your domicile home is in Colorado or you lived there more than 183 days of the past year you are a resident of Colorado. If you are a Colorado resident you will need to file a Colorado income tax return. You will use Form-104 (see attached) to file your taxes. For additional information on filing Form-104 see the included Instructions.

Colorado bases your taxes off your federal return so there are no deductions or exemptions on Form-104 because all deductions and exemptions were already calculated in your federal return.

On Form-104 you will perform certain additions and subtractions to the federal taxable income and then be taxed a flat rate of 4.63% on this amount.

Related Tax Forms

  • Form 104 - Colorado Individual Income Tax Return

Colorado Residents who lived in Colorado for part of the year

You were a part year resident of Colorado if you moved into or out of Colorado during the past year. If you are a part-year resident that needed to file a federal tax return you may need to also file a tax return with Colorado. For how to file a Colorado return during the time that you were a resident or resident working in another state see the Colorado Resident or Resident Working In Another State section. For how to file a Colorado return during the time that you were a nonresident working in the state or nonresident who sold property see the Colorado Nonresident Working In State or Nonresident Who Sold Property In State section.

Colorado Residents who work in another state

If your domicile home is in Colorado or you lived there more than 183 days of the past year you are a resident of Colorado. If you are a Colorado resident you will need to file a Colorado income tax return. You will use Form-104 (see attached) to file your taxes. For additional information on filing Form-104 see included Instructions.

Colorado bases your taxes off your federal return so there are no deductions or exemptions on Form-104 because all deductions and exemptions were already calculated in your federal return.

On Form-104 you will perform certain additions and subtractions to the federal taxable income and then be taxed a flat rate of 4.63% on this amount.

If you are a resident who works in another state you will need to complete several additional steps in filing your Colorado return to avoid dual taxation on income earned by states other than Colorado. The first step is to complete your federal tax return (in the same way that you would if you were a resident who lived and worked in Colorado). The second step is to complete the income return that you need to file for the other state that the income was eared in. The third step to file your Colorado return. To do this you will need to fill out Colorado Form 104 lines 1 through 18 only. Next you will fill out lines 20, 21, ad 24 of Colorado Form 104CR.

Both Forms 104 (with instructions included) and Form 104CR are attached.

Related Tax Forms

  • Form 104CR - Individual Credits Schedule
  • Form 104 - Colorado Individual Income Tax Return

Nonresidents who work in Colorado

If your domicile (permanent) home was not in Colorado for any part of the year, even though you might temporarily reside or work in Colorado, you are a nonresident of Colorado. If you are a nonresident of Colorado who filed a federal income return and had income from a Colorado source or have a Colorado tax liability you maybe required to file a Colorado nonresident return. Please note that there is no minimum income threshold. To file a nonresident Colorado return you will need to use Form-104PN. For more information see FYI Part-Year Residents and Non Residents.

Related Tax Forms

Nonresidents who sold property in Colorado

If your domicile (permanent) home was not in Colorado for any part of the year, even though you might temporarily reside or work in Colorado, you are a nonresident of Colorado. If you are a nonresident of Colorado who filed a federal income return and had income from a Colorado source or have a Colorado tax liability you maybe required to file a Colorado nonresident return. Please note that there is no minimum income threshold. To file a nonresident Colorado return you will need to use Form-104PN. For more information see FYI Part-Year Residents and Non Residents.

Related Tax Forms

Colorado Tax Forms


Relevant Links