Things to know when you’re filing a Colorado state tax return

Lake Helene is a scenic peak in Colorado's Rocky Mountain National Park. Image:

In a Nutshell

Coloradans can take advantage of a wide range of tax credits and deductions while filing state income tax returns. That, plus a simple tax structure, may make filing your Colorado state taxes much easier than filing in many other states. Here are things to know to complete the process.

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This article was fact-checked by our editors and reviewed by Jennifer Samuel, senior product specialist for Credit Karma Tax®. It has been updated for the 2019 tax year.

You may think you’d rather hike the Rockies in flip-flops carrying a 100-pound backpack than do your Colorado state tax return.

But filing taxes in the state that’s home to the Rocky Mountains doesn’t have to be difficult. Colorado has a simple tax structure with a single individual income tax rate that applies to everyone who has to pay tax to the Centennial State. Plus, plenty of state-level deductions and credits are available to help taxpayers reduce their state tax burden.

Let’s look at things to know about filing a Colorado state tax return.


The basics of Colorado state taxes

Colorado has several taxes, including a use tax, sales tax, marijuana taxes and county-level property taxes. In addition, Colorado has an income tax, and you may have to file a Colorado state tax return if you:

  • Are a all full-time Colorado resident
  • Lived and worked in the state temporarily
  • Are a non-resident who earned income from Colorado
  • Had to file a federal return with the IRS

Taxing body

The Colorado Department of Revenue collects and administers state taxes. You can get help by phone and in person by:

  1. Calling 1-303-238-7378 with general tax questions between 8 a.m. to 4:30 p.m. Mountain time Monday to Friday
  2. Emailing your questions to DOR_TaxpayerService@state.co.us
  3. Mailing to Colorado Department of Revenue, PO Box 17087, Denver, CO 80217-0087
  4. Visiting one of several Taxpayer Service Locations around the state

Filing and payment deadline

Generally, April 15 is the due date for filing your Colorado state tax return and paying any tax you owe. If the 15th falls on a holiday or a weekend, the annual deadline will be bumped to the following business day.

Filing statuses

Colorado requires you to use the same filing status on your state return as on your federal tax return. The filing statuses are single, married filing jointly, married filing separately, head of household or qualifying widow(er) with dependent child.

Colorado income tax rate

Calculating your Colorado state income tax is easy, because the state has a flat tax rate of 4.5%. Multiply your taxable income by 0.045 to figure out how much tax you need to pay.

Learn more about federal income tax rates and tax brackets

Colorado deductions and credits to know

  • Child care contribution credit: If you made a qualifying donation (not a payment for services) to a licensed child care facility or qualifying program (such as the Denver Boys and Girls Club), you can take a tax credit of up to half of the qualified amount. The amount of the credit is capped at $100,000. The credit is nonrefundable, but you can carry forward any leftover credits for up to five tax years.
  • Child care expenses tax credit: If you spent money on child care for your own children and meet income thresholds and Colorado residency requirements, you may be able to claim this state-level tax credit. It’s worth 25% of your childcare expenses, up to $500 for one child or $1,000 for two or more children.
  • Earned income tax credit: If you claimed the earned income tax credit on your federal income tax return, you could claim it on your Colorado state tax return too, as long as you met state residency requirements. On your Colorado taxes, the credit is worth 10% of however much you received for the credit on your federal tax return. This is a refundable credit, which means if it’s greater than the amount you owe in taxes, you can get the rest back as a refund.
  • Innovative motor vehicle credit: If you bought, leased or converted a qualified electric vehicle or hybrid, you might be eligible to receive a tax credit. The amount of the credit depends on multiple factors, such as the type of vehicle, weight of the vehicle and when you bought it. Check which vehicles qualify and other conditions.
  • Long-term care insurance credit: If you’ve purchased a long-term care insurance policy, you may be able to receive a credit per policy. To qualify, you’ll need to meet income limits for your filing status and other requirements. Generally, the credit is worth 25% of the amount you paid for the policy during the tax year, up to $150 per policy.
  • First-time homebuyer savings account deduction: This deduction allows homebuyers to deduct any taxable interest or earnings from a savings account that they designate specifically for the purchase of their first home in the year claimed.
  • Charitable contribution deduction: You may be able to claim this deduction if you took the standard deduction on your federal return and you’ve donated money or property to a church (or other place or worship) or qualified nonprofit organization, including educational and medical group — and more importantly, kept your receipts. Caps apply.
  • 529 plan deduction: If you save for college expenses in a 529 savings plan, you can deduct those contributions or payments from your income on your Colorado state tax return as long as the amount was included in your income on your federal return and was directed to qualified state tuition programs.

How to file your Colorado state tax

You can e-file your Colorado state tax return through the Department of Revenue’s free Revenue Online service. However, if this is your first year filing as a resident, you won’t have access to this handy tool until you’ve filed at least one state return.

You can also use tax preparation software, such as Credit Karma Tax®. A free tax filing service, Credit Karma Tax never charges to help you prepare and file your single-state and federal income tax returns.

If you’d prefer to go the paper route (or if you’re doing your taxes and it’s your first year of filing a Colorado state tax return), you can print out a paper copy of Form 104 (the state income tax return form) and mail it to one of these addresses with your payment:

If you include a tax payment:
Colorado Department of Revenue
Denver, CO 80261-0006

If you don’t include a tax payment:
Colorado Department of Revenue
Denver, CO 80261-0005

What if you need help with your taxes? Aside from contacting the state directly, the Piton Foundation, a nonprofit that supports low-income Colorado families, offers free in-person tax return preparation and filing at various locations to households making less than an established income threshold.

Is e-filing a better way to file your taxes?

If you owe and can’t pay

If you’re having trouble paying your taxes by the due date, you may be able to take advantage of the Colorado Department of Revenue’s monthly installment plan. You can set this plan up through the state’s online portal, Revenue Online, or by calling the department at 1-303-205-8291.

Tracking your Colorado tax refund

You can track your tax refund status online by providing information, including your Social Security number, the amount of your refund and your PIN/Letter ID sent by the Department of Revenue.


Bottom line

Colorado offers a lot of options for tax credits and deductions. That potentially means a bigger refund check for you at the end of the year if you overpaid your taxes. But to get that money (or find out if you owe any money instead), you’ll first need to file your Colorado state taxes.


Jennifer Samuel, senior tax product specialist for Credit Karma Tax®, has more than a decade of experience in the tax preparation industry, including work as a tax analyst and tax preparation professional. She holds a bachelor’s degree in accounting from Saint Leo University. You can find her on LinkedIn.