Colorado Income Tax Filing: DR 0104, Extension and Retiree Rules

Updated October 25, 2026

Where Colorado tax starts

Most states start with federal adjusted gross income. Colorado starts with your federal taxable income, then adds and subtracts items the way Colorado law requires. So you need your federal return finished before you begin.

Colorado charges one rate on Colorado taxable income, and the rate changes from year to year. The Department of Revenue's guide lists the rate for each recent tax year. For lower incomes, the Department publishes tax tables that approximate the tax at that year's rate.

Colorado also has its own alternative minimum tax. It is based mostly on the federal one, so a person who owes federal minimum tax will probably owe the Colorado version too. Many Colorado credits are refundable, which means a credit larger than your tax can come back to you.

Retirees, military and credits the state lists

The Department's page for seniors and retirees lists subtractions and credits you may be able to claim:

• A subtraction for pension, annuity, IRA, disability and Social Security income.
• A military retirement benefits subtraction.
• A subtraction for public retirement plans, called PERA and DPSRS.
• Subtractions for qualifying charitable contributions and CollegeInvest contributions.
• A long-term care insurance credit and an income-qualified senior housing credit.
• A property tax, rent and heat rebate, plus the TABOR state sales tax refund.

The age tests and limits for these change, so read the Department's page for your tax year before you decide what to claim. Military families should also read the Department's publication on servicemembers, because federal and state law both affect residency.

Due dates, the extension and paying

Colorado returns are due April 15. Colorado gives every individual an automatic six-month extension to October 15 for calendar-year filers. There is no form to file, and no notice to send.

The catch is payment. There is no extension for tax due. The Department says you must pay at least the share of your tax that it names on its page by April 15 to avoid penalties. Any balance left after that is subject to interest only. Pay through Revenue Online, or mail the Extension Payment Form, DR 0158-I. If you expect a refund, you can still use the extension.

If a due date lands on a weekend or legal holiday, the next business day applies. You can e-file through Revenue Online or an IRS e-file option, or file on paper. Our extension guide covers the federal side.

Estimated payments for freelancers and investors

If you earn income with no Colorado tax withheld, you may need to pay four times a year. The Department's guide says estimated payments are required when your tax, after withholding and credits, passes a set amount.

• Due dates: April 15, June 15, September 15 and January 15. A weekend or holiday moves each date to the next business day.
• Worksheet: the DR 0104EP form walks you through the math.
• How to pay: Revenue Online takes card or e-check payments without a login. You can also register for electronic funds transfer, or mail a check with a voucher.
• Prior-year shortcut: you may base payments on last year's tax, but only if you filed a Colorado return for a full 12 months last year.

Claim the payments on your DR 0104. Your Revenue Online account shows the record. Our estimated tax guide covers the federal rules.

Residents, part-year filers and nonresidents

You are a Colorado resident if Colorado is your domicile. You are also a resident if you keep a permanent place to live in Colorado and spend more than six months of the year here. The Department calls the second group statutory residents.

Domicile is where you consider home and plan to return. The Department says no single factor decides it, and it lists the evidence it weighs:

• a state tax return filed as a resident;
• a driver's license and vehicle registration;
• voter registration;
• where your spouse and dependents live;
• real property you own and use; and
• residency for college tuition.

A domicile lasts until you set up a new one. If you change domicile during the year, you are a part-year resident. You owe Colorado tax on all income while you were domiciled here, plus any Colorado-source income afterward. Nonresidents owe tax on Colorado-source income. Joint filers with only one Colorado resident add the Part-Year Resident/Nonresident schedule, DR 0104PN.

Moving to or from Florida

Leaving Colorado for Florida usually means a part-year Colorado return for the year you go. What matters is the date your domicile changed. The Department says a person who stays away temporarily is still domiciled in the old state, and that a college student who moves for school has not changed domicile.

The same list of domicile evidence works as a checklist. The Department weighs these items together, so check that yours point to where you really live. Read our moving to Florida tax page for the Florida side.

Mistakes that cost Colorado filers

• Treating the extension as a payment extension. Interest still runs on late tax, and penalties can apply if you paid too little by April 15.
• Starting from adjusted gross income. Colorado starts from federal taxable income.
• Skipping DR 0104PN on a joint return when one spouse is not a Colorado resident.
• Filing separately for Colorado after a joint federal return. The statuses must match.
• Missing quarterly payments on freelance or investment income.
• Assuming a divorce ends your joint tax debt. The guide says both spouses on a joint return owe the full amount, even if a divorce order says otherwise.

See our tax deadlines page for federal dates.

Filing from Colorado with Zero Fuss Taxes

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FAQ

Sources

• tax.colorado.gov/income-tax-due-dates-filing-extension
• tax.colorado.gov/individual-income-tax-estimated-payments
• tax.colorado.gov/individual-income-tax-guide
• tax.colorado.gov/seniors-and-retirees-tax-benefits
• irs.gov/filing/individuals/when-to-file

General information, not tax advice for your specific situation. Rules can change, so check the official sources below. Zero Fuss Taxes is a PTIN-holding tax preparation firm. We are not a CPA firm, enrolled agents or attorneys.