Colorado Income Tax Calculator: Estimate Your CO State Taxes (2025)

Complete Guide: Colorado Income Tax Calculator: Estimate Your CO State Taxes (2025)

Calculate your CO liability with our 2025 Colorado income tax calculator. Uses the current CO flat tax rate for accurate estimation. Free CO tax calculator.

Colorado has a flat state income tax. That means the same rate applies to each dollar of your Colorado taxable income, regardless of how high or low your earnings are. Your taxable income starts with federal taxable income, so standard deduction amounts and pre‑tax contributions matter. This calculator mirrors that flow to give you a clear, realistic estimate.

How Colorado state income tax works

Colorado applies a flat 4.40% state income tax rate for tax year 2025. The state typically begins with your federal taxable income (after the federal standard deduction or itemized deductions) and then applies Colorado additions, subtractions, and credits. The output is your net Colorado tax. Our tool approximates this by taking your annual income, subtracting pre‑tax deductions and the federal standard deduction for 2025, and then applying the state rate. Finally, we let you reduce the bill with any Colorado credits you qualify for.

Key inputs you can control

• Annual income: Salary, bonuses and other wage income you expect for the year.
• Filing status: Determines the federal standard deduction baseline used in Colorado's calculation start point.
• Pre‑tax deductions: 401(k), HSA, FSA and other deductions lower your taxable income.
• Colorado credits: Enter your total state credits (e.g., Colorado Child Tax Credit, Earned Income Tax Credit) to reduce the final tax.

2025 federal standard deduction (used as a baseline)

Because Colorado starts from federal taxable income, the federal standard deduction is an important factor. For 2025, we use commonly reported indexed amounts as an approximation in this tool: $15,300 (Single), $30,600 (Married Filing Jointly), $15,300 (Married Filing Separately), and $22,950 (Head of Household). If you itemize federally, the comparable total deduction would replace this baseline.

Example: quick scenarios

Single, $75,000 income, $5,000 pre‑tax contributions

1. Adjusted gross income ≈ $75,000 − $5,000 = $70,000
2. Taxable income ≈ $70,000 − $15,300 (standard deduction) = $54,700
3. CO tax before credits ≈ $54,700 × 4.40% = $2,406.80
4. Subtract any Colorado credits to get your final bill

Married Filing Jointly, $120,000 income, $10,000 pre‑tax

1. Adjusted gross income ≈ $120,000 − $10,000 = $110,000
2. Taxable income ≈ $110,000 − $30,600 (standard deduction) = $79,400
3. CO tax before credits ≈ $79,400 × 4.40% = $3,493.60
4. Apply any state credits to reduce what you owe

Tips to lower your Colorado tax

• Maximize pre‑tax retirement contributions (401(k), 403(b), 457) and health accounts (HSA/FSA) when eligible.
• Review eligibility for refundable Colorado credits like the state Earned Income Tax Credit.
• Coordinate deductions and credits with your spouse's income if you file jointly.
• Run multiple scenarios in the calculator to see the impact of savings, credits and income changes.

What this calculator does

The calculator focuses on clarity: you enter income, filing status, pre‑tax deductions and estimated Colorado credits. We calculate an approximate Colorado taxable income and apply the state rate. The Summary panel shows your before‑credit tax, credits and final state tax alongside your after‑tax income.

How to interpret results

Use the effective rate to compare scenarios. If you plan to itemize at the federal level, remember that Colorado starts from federal taxable income, so your itemized total would replace the standard deduction assumption we show here.