Colorado Income Tax Brackets (2026)

Colorado levies a flat income tax of 4.4% on all taxable income. Unlike graduated-tax states where rates escalate with income, every dollar you earn in Colorado is taxed at the same 4.4% rate. This simplicity means your effective state tax rate is essentially the same whether you earn $50,000 or $500,000.

The practical advantage of a flat tax is predictability: if your income doubles, your state tax exactly doubles. In a graduated state like California (1\u201313.3%), a doubling of income could more than double your state tax as more of it falls into higher brackets.

Your total income tax is the sum of federal and Colorado state taxes. At each income level, an additional dollar is taxed at your federal marginal rate plus the state marginal rate. This combined marginal rate tells you how much of each additional dollar goes to taxes.

At $200K income, your combined marginal rate in Colorado is 28.4% — meaning each additional dollar is split roughly 28¢ to taxes and 72¢ to you. Even at $50K, the combined marginal rate is already 16.4%. This is why tax-advantaged strategies become increasingly valuable at higher incomes.

While you can’t change the bracket structure, several strategies can reduce the income that’s subject to Colorado’s 4.4% flat rate:

401(k) / 403(b) contributions: In 2026, you can contribute up to $23,500 pre-tax ($31,000 if age 50+). This reduces both federal and Colorado taxable income. At Colorado’s 4.4% rate, maxing your 401(k) saves roughly $1,034 in state taxes alone.

HSA contributions: If you have a high-deductible health plan, contribute up to $4,300 (individual) or $8,550 (family) to an HSA. These contributions are exempt from both federal and state income tax in Colorado.

Itemizing deductions: If your state and local taxes (SALT), mortgage interest, and charitable contributions exceed the standard deduction, itemizing can reduce your federal tax. The federal SALT cap of $10,000 limits how much of your Colorado state tax you can deduct federally.

Traditional IRA: If you’re not covered by an employer plan (or your income is below the phase-out), a traditional IRA contribution of up to $7,000 ($8,000 if 50+) reduces both federal and state taxable income.

How does Colorado’s flat 4.4% tax compare to nearby states? Here’s a side-by-side at $100K income:

Every state ranked by state income tax burden at $100K income. Colorado is highlighted at position #35.