How to Use This Calculator
Enter your income, filing status, and any deductions. The calculator computes your Colorado state income tax alongside your federal tax, showing exactly how much goes to each and what you take home.
The most useful thing to try? See how Colorado's flat 4.4% rate affects different income levels, then test how deductions and retirement contributions change your bottom line.
Here's what each field means:
Annual Income is your total earnings before any taxes. Include wages, freelance income, investment income, and any other sources.
Filing Status determines which deductions and exemptions apply. Colorado uses filing statuses similar to the federal system.
Colorado Income Tax: What You Need to Know
Colorado uses a flat income tax of 4.4% on all taxable income. Unlike states with progressive brackets, everyone pays the same percentage regardless of how much they earn. A teacher making $45,000 and a CEO making $500,000 both pay 4.4%.
Colorado uses a flat 4.4% income tax rate on all taxable income. The state's taxable income starts with your federal taxable income, which means Colorado automatically incorporates the federal standard deduction. This simplifies filing considerably — if you've already done your federal return, Colorado's calculation is straightforward. The rate was reduced from 4.55% to 4.4% effective in 2024 after voter approval of Proposition 121.
A Real Example
Let's say you're a single filer earning $80,000 in Colorado. After applying the standard deduction of $14,600, your approximate Colorado state income tax would be around $2,878, for an effective state tax rate of about 3.6%.
That's just the state portion. Federal income tax and FICA taxes are additional.
Deductions and Exemptions
Standard Deduction: $14,600 for single filers and $29,200 for married couples filing jointly.
Since Colorado starts with federal taxable income, you get the benefit of all federal deductions automatically. The state also offers additional subtractions for things like Colorado-source capital gains, pension/annuity income for those 55+, and contributions to Colorado 529 plans (CollegeInvest).
Local Taxes
Some Colorado cities levy local income or occupational privilege taxes. Denver charges a $5.75 monthly occupational privilege tax, and Aurora, Greenwood Village, and several other cities have similar small taxes.
Recent Changes
The flat rate dropped from 4.55% to 4.4% in 2024. Colorado's TABOR (Taxpayer's Bill of Rights) amendment requires voter approval for tax increases, which has helped keep rates stable or declining.
How to Use This Calculator Strategically
Model a raise or job change. With a flat tax, the math is simpler — every additional dollar is taxed at 4.4%. But deductions and credits can still shift your effective rate.
Compare filing statuses. Even with a flat rate, different filing statuses unlock different deduction amounts that can affect your bottom line.
Plan retirement contributions. See how 401(k) or IRA contributions reduce your Colorado taxable income and lower your state tax bill.
Evaluate a move. Compare Colorado's flat 4.4% rate to other states. Depending on your income level, a flat tax state might save you money — or cost you more — compared to a progressive system.
References
- Colorado Department of Revenue. (2025). Individual Income Tax.
This calculator is for educational purposes only and does not constitute tax or financial advice. Tax rates and rules change regularly. Consult a qualified tax professional for guidance specific to your situation.