Colorado collects state income tax on wages, retirement income, and investment gains

Colorado has a state income tax. The rate is a flat 4.40% on most income, which is lower than the national average but means you will owe state tax on wages, pensions, Social Security benefits, and capital gains if you live or work in Colorado.

The tax applies to residents and to nonresidents who earn income within the state. If you work in Colorado but live in another state, you may owe Colorado tax on that income. If you live in Colorado but work in another state, you typically owe tax only to the state where you work, though Colorado allows a credit for taxes paid to other states to prevent double taxation.

Colorado's income tax rate has been 4.40% since 2022. This is a single flat rate that applies regardless of how much you earn — unlike federal income tax, which uses tax brackets that increase with income.

Key Takeaways

  • Colorado's state income tax rate is 4.40% on all taxable income, applied as a flat rate rather than in brackets.
  • The tax applies to wages, self-employment income, retirement distributions, Social Security benefits, and investment gains.
  • You owe Colorado income tax if you are a resident or if you earned income within the state during the tax year.
  • Colorado allows a credit for income taxes paid to other states, so you typically do not pay tax twice on the same income.

Who owes Colorado income tax

You owe Colorado state income tax if you are a resident of Colorado for the entire tax year. Residency is determined by where you maintain your permanent home. If you moved to Colorado partway through the year, you owe tax only on income earned after you became a resident.

Nonresidents also owe Colorado income tax, but only on income earned within the state. This includes wages from a Colorado employer, self-employment income from a Colorado business, rental income from Colorado property, and capital gains from the sale of Colorado real estate.

Military members stationed in Colorado are not considered residents for tax purposes and do not owe Colorado income tax on military pay, though they do owe tax on other income earned in the state.

What types of income are taxed

Colorado taxes earned income — wages, salaries, tips, and self-employment income. It also taxes unearned income: interest, dividends, capital gains, rental income, and distributions from retirement accounts.

Social Security benefits are taxable in Colorado if your total income exceeds certain thresholds. The threshold depends on your filing status and whether you have other income. For single filers, benefits become taxable if your adjusted gross income plus half your Social Security benefits exceeds $25,000. For married couples filing jointly, the threshold is $32,000.

Retirement distributions from 401(k)s, IRAs, and pensions are fully taxable as ordinary income. However, Colorado allows a deduction for retirement income if you are age 55 or older — up to $24,000 per person per year for distributions from may have access to retirement plans, and unlimited deductions for Social Security benefits and certain military pensions.

How Colorado income tax is withheld from paychecks

If you are an employee in Colorado, your employer withholds state income tax from each paycheck based on the W-4 form you complete. The withholding is calculated using the 4.40% flat rate applied to your taxable wages after standard deductions.

You can adjust your withholding by submitting a new W-4 to your employer. If you want more tax withheld (for example, if you have other income not subject to withholding), you can request additional withholding. If you want less withheld, you can claim more allowances, though this may result in owing tax at the end of the year.

Self-employed people do not have an employer to withhold tax, so they must pay estimated taxes quarterly to the Colorado Department of Revenue. Estimated tax payments are due on April 15, June 15, September 15, and January 15 of the following year.

Filing your Colorado income tax return

Colorado residents must file a state income tax return if they have Colorado source income and meet the filing threshold. The threshold varies by age and filing status but is generally around $14,600 for single filers under age 65 and higher for older filers and married couples.

You file using Form 104, the Colorado Individual Income Tax Return. The form is available on the Colorado Department of Revenue website. You can file by mail or electronically through the department's online system or through a tax software provider.

The filing deadline is the same as the federal deadline: April 15 of the year following the tax year. If you file your federal return late, your Colorado return is also considered late. You can request an extension, which gives you until October 15 to file, though taxes are still due by April 15.

Tax credits and deductions available in Colorado

Colorado offers several tax credits that reduce the amount of tax you owe. The Earned Income Tax Credit is available to low- and moderate-income workers and is calculated based on federal EITC rules. The Child and Dependent Care Credit covers expenses for childcare while you work. The Dependent Exemption Credit provides a credit for each dependent claimed on your return.

Colorado also allows a deduction for retirement income for residents age 55 and older. This deduction covers distributions from IRAs, 401(k)s, and pensions up to $24,000 per person per year. Social Security benefits and certain military pensions have unlimited deductions regardless of age.

Standard deductions in Colorado are tied to federal standard deductions. For 2024, the standard deduction is $14,600 for single filers, $29,200 for married couples filing jointly, and $21,900 for heads of household. These amounts increase each year with inflation.

What happens if you do not pay Colorado income tax

If you owe Colorado income tax and do not pay, the Colorado Department of Revenue can assess penalties and interest. The penalty for underpayment is typically 5% of the unpaid tax, plus interest calculated daily at a rate set by the department. If the underpayment is due to negligence, the penalty increases to 10%.

The department can also place a lien on your property, garnish your wages, or intercept your state and federal tax refunds to collect unpaid tax. If you cannot pay in full, you can request a payment plan. The department also offers an Offer in Compromise program for taxpayers facing genuine hardship, though approval is not may provide.

If you believe you do not owe tax or disagree with an assessment, you can file a protest with the Colorado Department of Revenue within 30 days of receiving the notice. The protest must explain your position and include supporting documentation.

Frequently Asked Questions

Do I have to pay Colorado income tax if I just moved here?

You owe Colorado income tax starting the day you become a resident. If you moved partway through the year, you owe tax only on income earned after your move-in date. You will need to file both a part-year resident return in Colorado and a return in your previous state for the portion of the year you lived there.

Is Social Security taxed in Colorado?

Social Security is taxable in Colorado if your total income exceeds $25,000 (single) or $32,000 (married filing jointly). However, Colorado allows an unlimited deduction for Social Security benefits, so even if your benefits are technically taxable, you can deduct them on your Colorado return, resulting in no tax owed on those benefits.

What if I work in Colorado but live in another state?

You owe Colorado income tax on wages earned in Colorado. You also owe tax to your home state on the same income. However, Colorado allows a credit for taxes paid to other states, and most states do the same, so you typically pay tax to only one state — usually the one where you work.

Can I deduct federal income tax from my Colorado return?

No. Colorado does not allow a deduction for federal income tax paid. You calculate Colorado tax based on your federal taxable income but cannot reduce that income by the amount of federal tax withheld or owed.

What if I disagree with a Colorado tax assessment?

You can file a protest with the Colorado Department of Revenue within 30 days of receiving the notice. The protest should explain why you believe the assessment is incorrect and include copies of supporting documents such as receipts, pay stubs, or correspondence with the department.