Colorado State Income Tax: What Filers Should Know
Colorado taxes income at a flat rate of 4.4%, meaning every dollar of taxable income is subject to the same rate, regardless of how much you earn. If you earned income while living in Colorado, even part-time, you likely need to file a state return.
What Is Colorado's State Income Tax Rate?
Colorado uses a flat 4.4% income tax rate for the 2025 tax year. Unlike states with graduated brackets, every Colorado taxpayer, from first-time filers to high earners, pays the same rate on their taxable income.
Colorado starts with your federal taxable income and then allows certain state-specific subtractions. Key items that may reduce your Colorado taxable income include:
- Social Security benefits: Colorado fully exempts Social Security income from state tax
- Pension and annuity income: Colorado offers a subtraction for pension and annuity income; the amount depends on your age
- U.S. government interest income: Income from federal obligations is excluded from state taxation
- Qualifying charitable contributions: Colorado allows a subtraction for certain contributions exceeding the federal deduction
- Military retirement pay: exempt from Colorado income tax if you are 55 or older
These subtractions are applied to Colorado Form DR 0104AD. E-file.com guides you through each applicable subtraction automatically when you e-file your state return.
Who Needs to File a Colorado State Tax Return?
You must file a Colorado state return if any of the following apply:
- You were a Colorado resident for all or part of the year and earned income while living there
- You are a non-resident who earned income from Colorado sources and are also required to file a federal return
- You are a part-year resident: you file as a part-year resident and report only income earned while you lived in Colorado
Colorado Tax Deadlines and Extensions
For most filers, Colorado's filing and payment deadlines are both April 15. Colorado grants an automatic extension to October 15 if you need more time to file, but any taxes owed are still due April 15, and you must pay at least 90% of the balance by then to avoid penalties and interest.
If you were living or traveling outside the U.S. on April 15, your filing deadline automatically extends to June 15. Active military in a combat zone have 180 days after their assignment ends to both file and pay.
You can e-file your Colorado state return directly through E-file.com, or mail a paper return to the Colorado Department of Revenue, Denver, CO 80261-0005.
Colorado Tax Penalties and Late Payment Fees
If you miss the deadline, Colorado charges separate penalties for failing to file and failing to pay, and both can apply at the same time. The failure-to-file penalty is the greater of $5 or 5% of the taxes due. On top of that, an additional 0.5% per month accrues on any unpaid balance, capped at 12%. Interest accrues separately and is adjusted annually. You can avoid the failure-to-pay penalty entirely by paying at least 90% of what you owe by April 15.
How to Check Your Colorado Tax Refund
After you file, you can check the status of your Colorado refund at any time using the Revenue Online system at tax.colorado.gov. You will need your name, Social Security number (or other identifying number), and mailing address to log in or create an account.
E-filed Colorado returns typically produce a refund within 3–5 weeks; paper returns can take up to 3 months.
How to File Colorado State Taxes With E-file.com
E-file.com lets you file your Colorado state return at the same time as your federal return, with no extra steps and no separate login. The software automatically walks you through state-specific subtractions and credits, including the TABOR credit if applicable.
E-file.com is an authorized IRS e-file provider. Your federal and state returns are transmitted electronically, and you receive an IRS confirmation number once accepted. File your Colorado state return today with E-file.com.
Frequently Asked Questions About Colorado State Taxes
How long does it take to get a Colorado state tax refund?
If you e-file, most Colorado refunds arrive within 3–5 weeks. Paper returns take up to 3 months. You can check the status of your refund anytime using Revenue Online at tax.colorado.gov. You will need your name, Social Security number and mailing address.
Does filing a Colorado extension give me more time to pay?
No. Colorado's automatic extension to October 15 gives you more time to file your return, not more time to pay taxes owed. You must still pay at least 90% of any Colorado taxes owed by April 15 to avoid late-payment penalties and interest. If you owe taxes and cannot pay in full, you should pay as much as possible by April 15 and set up a payment plan through Revenue Online.
Can I set up a payment plan if I cannot pay my Colorado tax bill in full?
Yes. The Colorado Department of Revenue offers installment agreements for taxpayers who cannot pay in full. You can request a payment plan through Revenue Online. While on a plan, penalties and interest continue to accrue on any unpaid balance, so paying as much as possible upfront reduces the total you owe.
What Is the TABOR Refund?
The TABOR refund, short for Taxpayer's Bill of Rights, is a credit Colorado distributes to residents when state revenues exceed the constitutional cap set by TABOR. When the state collects more than the limit, it returns the excess to Colorado taxpayers as a refundable credit on their state income tax return.
You do not need to do anything special to claim it. If you file a Colorado state return, the credit is applied automatically when you qualify.
Note: States & U.S. territories may make changes to their tax laws with little notice. We do our best to keep this information up-to-date, but it is provided on an "AS IS" basis. For more see our terms.