Individuals · Colorado filing

Colorado tax filing: file CO state taxes online, Form DR 0104, flat 4.4% rate

Colorado keeps the rate simple and the starting point unusual. It taxes all income at a single flat 4.4 percent, but it begins the calculation from your federal taxable income, the number after your federal deductions, rather than your adjusted gross income. That one design choice means there is no separate Colorado standard deduction to figure; the federal deduction is already baked in.

This page covers what Colorado requires for tax year 2025 returns filed in 2026: who has to file Form DR 0104, how the flat 4.4 percent rate and the federal-taxable-income basis work, the automatic extension, the way Social Security and pensions are subtracted, and the credits that make Colorado friendlier than the flat rate alone suggests. TaxFile prepares your federal and Colorado returns together from your W-2s and 1099s, finds the deductions and credits you qualify for, runs an error check, and e-files through an authorized IRS e-file provider after you review and approve every line. Pricing is $39 simple, $89 self-employed, $199 business, plus $19 per state return. This is self-prepared tax software, not personalized tax advice; for complex situations, consult a CPA or tax professional.

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The short answer

To file Colorado state taxes, you file Form DR 0104 with the Colorado Department of Revenue; part-year residents and nonresidents add Schedule DR 0104PN. For tax year 2025 Colorado taxes income at a flat 4.4 percent. Colorado is unusual because it starts from your federal taxable income, not federal AGI, so there is no separate Colorado standard deduction. The return is due April 15, 2026, with an automatic six-month extension to file and no form required. There is no city income tax on the return, and Social Security is largely subtracted for older filers.

Last updated July 2026

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What you get with Colorado tax filing

Flat 4.4 percent rate

For tax year 2025 Colorado taxes all taxable income at a flat 4.4 percent. There are no brackets, so the rate is the same whether you earn $30,000 or $300,000.

Starts from federal taxable income

Colorado begins with your federal taxable income, not AGI, so your federal standard or itemized deduction is already reflected and there is no separate Colorado standard deduction to compute.

No city income tax on the return

Colorado has no municipal income tax on the state return. A few cities like Denver charge a flat monthly occupational privilege tax through payroll, but it is not filed on your DR 0104.

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TaxFile reads your W-2s, 1099s and receipts, classifies your income, finds the deductions and credits you qualify for, runs an error and audit-risk check, and assembles a return you review and approve before filing.

Shows whether your income requires a Colorado return
Applies the flat 4.4 percent rate to your federal taxable income
Prepares the federal and Colorado DR 0104 returns from one set of documents
Claims the Social Security subtraction, EITC and Child Tax Credit you qualify for
E-files through an authorized IRS e-file provider after you review and approve

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Self-employment tax deduction $6,120

Home office (simplified) $1,500

QBI deduction $2,880

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Do you have to file a Colorado tax return?

You generally must file a Colorado DR 0104 for 2025 if any of these are true:

You are required to file a federal return as a full-year resident, a part-year resident, or a nonresident with Colorado-source income.
You have a Colorado income tax liability for the year.
You want a refund of Colorado withholding or a refundable credit such as the TABOR sales tax refund, the state EITC, or the Child Tax Credit.

Full-year residents file Form DR 0104. Part-year residents and nonresidents file the same form with the DR 0104PN apportionment schedule, which prorates the tax to the income sourced to Colorado. The current rules are published by the Colorado Department of Revenue, and the state tax filing pillar compares Colorado with the other states.

The flat rate and the federal-taxable-income starting point

Colorado is a flat-tax state. For tax year 2025 it taxes all taxable income at 4.4 percent. The statutory rate is 4.4 percent, and it can be temporarily lowered in a year when the state has to refund a large surplus under the Taxpayer's Bill of Rights (TABOR); it was briefly 4.25 percent for 2024 but returned to 4.4 percent for 2025.

What makes Colorado different from other flat states is where the math starts. Most states begin from federal adjusted gross income. Colorado begins from federal taxable income, the figure on your federal return after your standard or itemized deduction. Because that deduction is already reflected, Colorado has no separate standard deduction. From that starting number, Colorado adds a few items back and subtracts others on Schedule DR 0104AD, then applies the flat 4.4 percent.

Step	Colorado treatment
Starting point	Federal taxable income (not AGI)
Standard deduction	None separately; the federal deduction is already included
Rate	Flat 4.4 percent on Colorado taxable income
Adjustments	State additions and subtractions on Schedule DR 0104AD

Social Security, retirement income and Colorado credits

Colorado gives a generous pension and annuity subtraction, and the Social Security rules were expanded for 2025:

Age 65 or older: you can subtract the entire amount of federally taxed Social Security benefits, and Social Security does not count against the general $24,000 pension and annuity cap.
Age 55 to 64 (new for 2025): you can subtract all federally taxed Social Security if your adjusted gross income is $75,000 or less (single) or $95,000 or less (married filing jointly). Above those limits, Social Security falls under the general pension cap instead.
General pension and annuity subtraction: up to $20,000 for ages 55 to 64 and up to $24,000 for 65 and older, covering pensions, annuities, and IRA and 401(k) distributions.

Colorado also offers strong credits that reduce the flat-rate bill:

Credit	What it does
Colorado EITC	50 percent of the federal Earned Income Tax Credit for 2025, one of the largest state matches in the country. Refundable.
Colorado Child Tax Credit	A refundable credit for families with young children, phased down by income, on Schedule DR 0104CN.
TABOR sales tax refund	A refundable credit for qualifying full-year residents when the state collects surplus revenue, claimed on the DR 0104.

Colorado filing deadline, extension and filing online

Date	What it means for a 2025 Colorado return
April 15, 2026	DR 0104 due, and any balance owed is due in full
April 15, 2026	Pay at least 90 percent of tax owed to avoid a penalty
October 15, 2026	Extended filing deadline (automatic, no form required)

Colorado's deadline is April 15, 2026 for tax year 2025 returns. Colorado grants an automatic six-month extension to October 15, 2026, and you do not file any extension form to get it. If you owe, you must pay at least 90 percent of your Colorado tax by April 15, 2026 to avoid a penalty, with the balance due by the extended date. Use the DR 0158-I voucher only if you are mailing an extension payment; it is not needed to obtain the extension or if you pay electronically.

Filing electronically is the practical default, and the Colorado return builds directly on your federal figures. TaxFile prepares both from one pass:

Upload or talk. Drop in your W-2s and 1099s and it reads them, or describe your year and it asks what it needs.
Federal and Colorado together. One set of documents produces both returns, carrying your federal taxable income into the DR 0104 and applying the flat 4.4 percent.
Credits checked. It applies the Social Security subtraction, the state EITC, and the Child Tax Credit where they fit.
Error check, then you approve. Nothing is e-filed until you review and approve every line, through an authorized IRS e-file provider.

Pricing is $39 for a simple return, $89 self-employed, $199 business, plus $19 for each state return. There is no free tier. If your Colorado income comes from contract or freelance work, self-employed tax filing covers Schedule C and Schedule SE in more detail. TaxFile does not e-file federal extensions or prepare amended returns, and does not handle capital gains on Schedule D, rental income on Schedule E, or cryptocurrency. TaxFile is self-prepared tax software and does not provide personalized tax advice, and no refund amount is guaranteed.

Good questions

Questions about colorado filing

You generally must file a Colorado DR 0104 for 2025 if you are required to file a federal return as a resident, part-year resident, or nonresident with Colorado income, or if you have a Colorado tax liability. You should also file to claim a refund of withholding or a refundable credit like the TABOR sales tax refund, state EITC, or Child Tax Credit.

Colorado taxes all taxable income at a flat 4.4 percent for tax year 2025. There are no brackets, so every filer pays the same rate. The rate can be temporarily reduced in a year when the state refunds a large TABOR surplus; it was 4.25 percent for 2024 but returned to the statutory 4.4 percent for 2025.

No. Colorado starts its calculation from your federal taxable income, which is the amount after your federal standard or itemized deduction, so there is no separate Colorado standard deduction. Colorado then applies additions and subtractions on Schedule DR 0104AD and taxes the result at a flat 4.4 percent.

Colorado returns for tax year 2025 are due April 15, 2026. Colorado grants an automatic six-month extension to October 15, 2026 with no form required, but you must pay at least 90 percent of your tax by April 15 to avoid a penalty. Use the DR 0158-I voucher only if mailing an extension payment.

Largely no for older filers. Filers 65 or older can subtract all federally taxed Social Security benefits. For 2025, filers aged 55 to 64 can also subtract all of it if their AGI is $75,000 or less (single) or $95,000 or less (married filing jointly). Colorado also allows a pension and annuity subtraction of up to $20,000 to $24,000 depending on age.

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