Colorado taxes your income at a flat rate, currently 4.40 percent

Colorado has a flat income tax, meaning everyone pays the same percentage regardless of how much you earn. As of 2024, that rate is 4.40 percent on federal taxable income. This is one of the lowest state income tax rates in the country, but it applies to wages, self-employment income, capital gains, and most other income sources.

The tax is calculated on your federal taxable income — the number you report to the IRS on your Form 1040 — rather than on a separate Colorado calculation. This simplifies filing, but it also means federal deductions and credits flow through to your Colorado return.

Colorado does not have separate tax brackets or progressive rates. Whether you earn $30,000 or $300,000, you pay 4.40 percent on the income subject to tax. Some income is excluded entirely, and you get a standard deduction, but the rate itself never changes.

Key Takeaways

  • Colorado's flat tax rate of 4.40 percent applies to all income levels, with no higher brackets for higher earners.
  • The tax is calculated on your federal taxable income, so federal deductions and adjustments affect what Colorado taxes.
  • You must file a Colorado return if you are a resident and earn above the standard deduction threshold, even if you owe no federal tax.
  • Certain income types — including Social Security, some retirement distributions, and military pay — may be partially or fully exempt from Colorado tax.
  • The state rate can change year to year through legislation, so confirm the current rate when you file.

Who must file a Colorado return

You must file a Colorado income tax return if you are a resident of Colorado and your income exceeds the standard deduction for your filing status. Colorado residency is determined by where you live for more than six months of the year, though the rules are more complex if you move mid-year or work across state lines.

Even if you owe no federal tax, you may still owe Colorado tax, or you may file to claim a refund of taxes withheld. The filing requirement is separate for each state, so living in Colorado means you file both a federal return and a Colorado return if your income is high enough.

Non-residents who earned Colorado-source income — such as wages from a Colorado employer or self-employment income from Colorado clients — must also file, but only on that Colorado income, not on out-of-state earnings.

Standard deduction and personal exemptions

Colorado allows a standard deduction that reduces the income subject to tax. The amount depends on your filing status and age. For 2024, the standard deduction ranges from roughly $3,850 for a single filer to $7,700 for married filing jointly, though these amounts adjust annually for inflation.

Colorado also allows a dependent exemption of approximately $3,850 per dependent (adjusted yearly), which further reduces taxable income. This is in addition to the standard deduction, not instead of it. If you itemize deductions on your federal return, you can also itemize on your Colorado return, though most filers use the standard deduction.

These amounts change each year, so check the current year's Colorado Department of Revenue guidance before calculating your tax liability. The state publishes updated figures in early spring.

Income that is not taxed in Colorado

Colorado exempts certain types of income from state tax even though they may be taxable federally. Social Security benefits are not taxed in Colorado. Military retirement pay and some federal retirement income also receive preferential treatment, though the rules vary by program and when you earned the income.

Long-term capital gains received preferential treatment under a now-expired law, but that exemption ended after 2023. Gains realized in 2024 and later are taxed at the full 4.40 percent rate. If you sold investments in late 2023 to take advantage of the exemption, that timing decision affected your 2023 return, not your 2024 return.

Certain retirement distributions, including may have access to distributions from Roth IRAs and some distributions from 401(k)s and traditional IRAs, may be partially exempt if you meet age and holding-period requirements. The exemption is not automatic — you must claim it on your return or request it from your plan administrator.

How to file your Colorado return

Colorado uses the federal tax form as a starting point. You file Form 104 (the Colorado individual income tax return) after you complete your federal Form 1040. The state return is much shorter than the federal form because it uses your federal taxable income as the baseline and then makes only Colorado-specific adjustments.

You can file on paper by mailing Form 104 and any schedules to the Colorado Department of Revenue, or you can file electronically through approved tax software or a tax professional. E-filing is faster and reduces errors, and the state offers free filing software through the IRS Free File program if your income is below a certain threshold.

The important date to file is the same as the federal important date — usually April 15 — unless you request an extension. An extension gives you until October 15 to file, but it does not extend the important date to pay any tax owed. Estimate your liability and pay by April 15 to avoid penalties and interest.

Tax withholding and estimated payments

If you are an employee, your employer withholds Colorado income tax from your paycheck based on the W-4 form you complete. The withholding is calculated to approximate your annual tax liability, but it may be too high or too low depending on your circumstances. You can adjust your withholding by submitting a new W-4 to your employer.

If you are self-employed or have income not subject to withholding — such as rental income, investment income, or business profit — you may need to make estimated tax payments quarterly. These are due on April 15, June 15, September 15, and January 15 of the following year. Underpayment can result in penalties even if you ultimately owe no tax or receive a refund.

Use Form 104-ES to calculate your estimated payment, or work with a tax professional to determine the right amount. Paying too little triggers a penalty; paying too much straightforward means you receive a refund when you file your return.

Deductions and credits available in Colorado

Colorado allows you to claim the same federal deductions and credits on your state return, with a few exceptions. The child tax credit, earned income tax credit, and education credits generally flow through to Colorado. However, some federal credits are not allowed in Colorado, and some Colorado-specific credits exist that have no federal equivalent.

One notable Colorado credit is the child care and dependent care credit, which may be more generous than the federal version in certain situations. There is also a property tax exemption for seniors and disabled persons, though that is administered separately from the income tax return.

Because Colorado taxes federal taxable income, any deduction or adjustment you claim on your federal return automatically affects your Colorado tax. If you reduce your federal taxable income through a 401(k) contribution or student loan interest deduction, your Colorado taxable income is reduced by the same amount.

Frequently Asked Questions

Does Colorado tax retirement income differently?

Social Security is never taxed in Colorado. Pension and retirement account distributions are taxed at the full 4.40 percent rate unless they may have access to for a specific exemption. Some military pensions and federal retirement income receive partial exemptions, but you must claim them on your return. Roth IRA may have access to distributions may be exempt if you meet age and holding-period rules.

What happens if I move to Colorado mid-year?

You are a Colorado resident for tax purposes if you live in the state for more than six months of the year. If you move to Colorado partway through the year, you file a part-year resident return and report only Colorado-source income. If you move out of Colorado, you file a part-year resident return for the year you leave and report only income earned while you were a resident.

Can I deduct federal taxes paid on my Colorado return?

No. Colorado does not allow a deduction for federal income taxes paid. You can deduct state and local taxes (SALT) on your federal return up to $10,000, but that does not reduce your Colorado tax. The two returns are separate calculations.

Is the 4.40 percent rate locked in, or can it change?

The rate can change through state legislation. It has been 4.40 percent since 2020, but the state legislature can raise or lower it. Always confirm the current rate for the year you are filing, as the Department of Revenue publishes updates in early spring.

Do I owe Colorado tax if I work remotely for an out-of-state company?

Yes, if you are a Colorado resident, you owe Colorado tax on all income, including wages from an out-of-state employer. Your employer may not withhold Colorado tax, so you may need to make estimated payments or adjust your federal withholding to cover the state liability.