Colorado uses a flat state income tax of 4.4% in 2026 — the same rate applies to every dollar of taxable income, which makes your paycheck easy to predict. On a $75,000 salary, a single filer pays about $3,300 in state tax and takes home roughly $58,293 a year (about 77.7% of gross) after federal, state, and FICA withholding.

Colorado's 4.4% rate is below the 4.8% average among states that tax wage income. Because the rate is flat, a raise never pushes part of your income into a higher state bracket — every extra dollar is taxed at the same 4.4%, unlike the federal system where higher earnings hit progressively higher brackets.

Remember that FICA is separate from income tax and is not affected by your state. Every worker pays 6.2% for Social Security on the first $184,500 of wages (the 2026 wage base) plus 1.45% for Medicare on all wages. Pre-tax 401(k) and HSA contributions lower your federal and state income tax but do not reduce FICA — a detail that trips up a lot of first-time budgeters.

Colorado's flat income tax is written into a framework shaped by TABOR — the Taxpayer's Bill of Rights — which requires voter approval for tax increases and forces the state to refund surplus revenue. In strong budget years, Coloradans have received TABOR refunds at tax time, and the flat rate itself has been temporarily reduced in some years because of the surplus mechanism. Also note the FAMLI payroll deduction for the state's paid family and medical leave program, which appears as a separate line on Colorado pay stubs.