Filing and paying Colorado income tax
- Return
- Form DR 0104, due April 15. To avoid a late-payment penalty with an extension, pay 90% of the tax by April 15 and file by October 15.
- Withholding
- Employers use your federal W-4 unless you also file Colorado's DR 0004, which lets you match withholding to your actual deductions.
To see how Colorado sits against every other state on top rate, bracket count and standard deduction, see state income tax rates for 2026 — all 51 jurisdictions in one sortable table.
How Colorado Income Tax Compares to Neighboring States
Total income tax (federal + state) on a $100,000 annual salary in 2026, single filer using the standard deduction:
| State | State Tax | Total Income Tax | vs. Colorado |
|---|---|---|---|
| Colorado (here) | $3,692 | $16,862 | — |
| Wyoming | $0 | $13,170 | -$3,692 |
| Nebraska | $3,670 | $16,840 | -$21 |
| Kansas | $4,780 | $17,950 | +$1,089 |
| Oklahoma | $3,955 | $17,125 | +$263 |
| New Mexico | $3,569 | $16,739 | -$123 |
A negative "vs." figure means that state collects less total income tax than Colorado. Federal portion is identical across states; only state tax varies.
Frequently Asked Questions
What is the Colorado state income tax rate for 2026?
Colorado has a flat 4.4% state income tax rate for 2026. The rate is the same regardless of income — applied to taxable income after the standard deduction. Federal rates (10%–37%) layer on top.
How much income tax will I pay in Colorado on a $100,000 salary?
For a single filer earning $100,000 in Colorado in 2026, expect approximately $13,170 in federal income tax and $3,692 in Colorado state income tax — for a total income tax of about $16,862, an effective rate of 16.9%. This excludes FICA (Social Security and Medicare), which adds roughly 7.65% on top.
What is Colorado's income tax rate for 2026?
A flat 4.4% of Colorado taxable income, which starts from federal taxable income after the federal standard deduction.
How much is the Colorado TABOR refund for 2025?
Between $19 and $59 for single filers and $38 to $118 for joint filers, depending on modified AGI. It is claimed on the 2025 return, which full-year residents must file by October 15, 2026.
Does Colorado tax Social Security?
Not at 65 or older. Between 55 and 64 it is fully exempt if federal AGI is $75,000 or less ($95,000 joint); otherwise up to $20,000 is exempt.
Does Colorado have a local income tax?
No, but Denver and a few other cities charge a flat monthly occupational privilege tax on people who work there; Denver's employee share is $5.75 a month.
For the preferential federal rates on long-term gains, see the Capital Gains Tax Calculator. For the federal brackets, standard deduction, and Social Security wage base that sit underneath this state calculation, see 2026 Tax Calculators.