Flat Rate: 4.4%TABOR RefundsFederal ConformityLast reviewed June 2026

Colorado State Income Tax 2026

Colorado's flat income tax rate is 4.4% for 2026, applied to federal taxable income with limited state modifications. The Taxpayer Bill of Rights (TABOR) constitutional amendment returns surplus state revenue to taxpayers through periodic rate reductions or refund checks. Colorado taxes Social Security partially but the over-65 exclusion makes most retirees fully exempt.

Colorado 2026 Quick Facts

Tax type	Flat 4.4%
Previous rate (2021)	4.55%
Standard deduction	Conforms to federal
Local income tax	Occupational Privilege Tax in some cities ($2-5/mo flat)
Reciprocity agreements	None
Social Security taxed	Partial (full exemption at age 65+)
Military pension	Partial exemption up to $24,000 (age-dependent)
TABOR refund	Yes (when state revenue exceeds growth cap)
2026 changes	Rate held at 4.4%

2026 Colorado Income Tax Brackets

Rate	Single Filer Income	Married Filing Jointly
4.4%	All taxable income	All taxable income

Sources: Colorado Department of Revenue (tax.colorado.gov), Colorado Proposition 121 (2022 rate reduction), Colorado TABOR Constitutional Amendment (1992). Data verified May 2026.

Colorado Effective Rate Calculator

Annual Gross Income

Filing Status

Standard deduction: $15,000 applied before tax calculation.

Effective Rate

3.52%

State Tax Due

$2,640

Marginal Bracket

4.4%

State income tax only. Does not include federal income tax, Social Security, Medicare, or local income tax. Calculations are estimates for educational purposes. Verify with a licensed CPA before filing.

What You Actually Pay: Worked Examples

$50,000 income

State tax due$1,540

Effective rate3.1%

Marginal bracket4.4%

After state tax$48,460

$75,000 income

State tax due$2,640

Effective rate3.5%

Marginal bracket4.4%

After state tax$72,360

$100,000 income

State tax due$3,740

Effective rate3.7%

Marginal bracket4.4%

After state tax$96,260

$250,000 income

State tax due$10,340

Effective rate4.1%

Marginal bracket4.4%

After state tax$239,660

Single filer, standard deduction. Does not include federal tax, Social Security, or Medicare.

Local Income Tax in Colorado

Most Colorado cities do not levy a percentage-based local income tax. However, a small number of Colorado cities levy an Occupational Privilege Tax (OPT): a flat per-month fee paid by employees and employers, not a percentage of income.

Denver: $5.75 per month (employee) + $4 (employer) for those earning above $500/month in the city
Aurora: $2 per month employee + $2 employer
Glendale: $5 per month employee + $5 employer
Greenwood Village: $2 per month employee + $2 employer
Sheridan: $3 per month employee + $3 employer

For a Denver employee earning $75,000, the annual OPT is approximately $69 (employee portion). This is materially different from percentage income taxes in Pennsylvania or Ohio cities.

See the full local income tax guide for all US cities →

Colorado Filing Requirements

Residents: File Colorado Form 104 if you must file federal Form 1040. Colorado conforms to federal AGI as the starting point.

Part-year residents: File Form 104PN for the portion of the year you lived in Colorado.

Non-residents: File Form 104PN for Colorado-source income.

TABOR refund: When applicable, the TABOR refund is calculated and credited automatically as part of the Form 104 filing. Recent years have included direct refund checks (Colorado Cash Back) when revenue surpluses are sufficient.

Filing deadline: April 15. Extensions to October 15 available with Form DR 158.

Retirement Income Treatment in Colorado

Social Security benefits	Partial	Fully exempt at age 65+; partial exclusion below
Traditional pension income	Partial	Up to $24,000 exclusion (age-dependent)
Government pension	Partial	Same exclusion as private pension
Military pension	Partial	Up to $24,000 exclusion for retired military age 55+
401(k) and IRA withdrawals	Partial	Up to $24,000 retirement income exclusion (combined)
Roth IRA withdrawals	Exempt	Qualified distributions are tax-free

Colorado is moderately retirement-friendly. Social Security is fully exempt at age 65+ and the $24,000 retirement income exclusion is generous. Plus the TABOR refund mechanism returns surplus revenue to all taxpayers including retirees. See the full 50-state retirement income scorecard.

Colorado Income Tax: FAQs

What is Colorado's income tax rate for 2026?

Colorado has a flat income tax rate of 4.4% for 2026, applied to all taxable income. This rate was reduced from 4.55% effective tax year 2022 by Proposition 121 (passed November 2022). Colorado's flat-rate structure has been in place since 1987 when the state moved from graduated brackets to a single flat rate.

What is the TABOR refund?

The Taxpayer Bill of Rights (TABOR) is a Colorado constitutional amendment passed in 1992 that requires the state to refund revenue collected above certain growth limits. When state revenue exceeds the TABOR cap, the surplus is returned to taxpayers, typically through a temporary income tax rate reduction or direct refund check. Recent TABOR refunds have ranged from a few hundred to over $1,000 per filer depending on the year.

Does Colorado tax Social Security?

Partially. Colorado is one of the 9 states that taxes Social Security, but with significant age-based exclusions: taxpayers 65 and older can fully exclude Social Security from Colorado taxable income. Younger taxpayers may also exclude up to certain limits. Effectively, most Colorado retirees have Social Security fully exempt from state tax.

Does Colorado have a local income tax?

Generally no, but there are exceptions. Most Colorado cities do not have an income tax, but Denver, Aurora, Greenwood Village, Glendale, Sheridan and a few other cities levy an Occupational Privilege Tax (OPT), which is a small flat-dollar amount (typically $2-5 per month) paid by employees and employers, not a percentage of income. This is functionally a flat fee, not a percentage income tax.

What is Colorado's standard deduction?

Colorado conforms to the federal standard deduction. For 2026, this is approximately $15,000 for single filers and $30,000 for married filing jointly (estimated inflation-adjusted figures). Colorado then applies the 4.4% flat rate to federal taxable income with limited state-specific modifications.

Sources: Colorado Department of Revenue (tax.colorado.gov), Colorado Proposition 121 (2022 rate reduction), Colorado TABOR Constitutional Amendment (1992). Data verified May 2026. Not tax advice. Always confirm current figures with the Colorado Department of Revenue or a licensed CPA or Enrolled Agent before filing.