Colorado state income tax — ITIN filer guide

Colorado taxes income at a flat 4.4% (tax year 2026), administered by the Colorado Department of Revenue — Taxation Division. This guide covers who must file, how filing with an ITIN works, whether the state EITC applies to you, and when refunds arrive.

FLAT rate: 4.4%

  • State return form: Form DR 0104
  • Deadline (tax year 2026): April 15, 2027 (automatic extension to file until October 15; payment due April 15)
  • Who must file: Must file if required to file a federal return or if you have Colorado income tax liability (no separate dollar threshold)
  • State sales tax: 2.9%
  • Special regime: Some localities levy small flat occupational privilege taxes on wages (e.g., Denver)
  • Scheduled change: Large TABOR surpluses can trigger temporary one-year rate cuts (mechanism cut the rate to 4.25% for 2024); baseline remains 4.40% for 2026

Colorado refund timing

State tax agency

  • Colorado Department of Revenue — Taxation Division — tax.colorado.gov
  • Phone: 303-238-7378
  • Free filing option: Revenue Online — DOR's free state e-file and account portal

Facts verified 2026-06-11 against official state sources (primary source). Figures refresh with every dataset review.

Filing with an ITIN

Your ITIN is fully accepted on the Colorado state return — states accept the IRS-issued taxpayer number, the same one you use federally. The flow is always the same:

  1. Complete your federal return first (Form 1040 + ITIN)
  2. Transfer your federal figures to Form DR 0104
  3. Apply state-specific deductions and credits
  4. E-file — Revenue Online — DOR’s free state e-file and account portal
  5. Or visit a VITA site for free in-person preparation

Colorado state EITC — do ITIN filers qualify?

The federal EITC requires valid SSNs for you, your spouse, and qualifying children — ITIN filers can never claim it. What varies is the STATE credit:

Colorado Earned Income Tax Credit (COEITC) — 50% of federal (TY2025); TY2026 ranges 25-50% depending on an inflation-adjustment trigger under HB24-1134 of the federal EITC (refundable)

✓ OPEN to ITIN filers

Filers who cannot claim the federal EITC because they, a spouse, or dependents use an ITIN claim the COEITC on Form DR 0104TN (state-confirmed)

State child tax credit: Colorado Child Tax Credit (children under 6, income-limited) plus Family Affordability Tax Credit up to $3,200/child under 6 and $2,400/child 6-16 (TY2024-25, AGI-capped); ITIN parents eligible for both

See how all 52 jurisdictions compare on the state tax hub and which tax credits ITIN filers can claim.

Last verified: 2026-06-11. Primary source: Colorado Department of Revenue — Taxation Division.

General procedural information for educational purposes. Not legal or tax advice. State tax rates change frequently — verify current figures with the state agency before filing. For case-specific guidance, consult a tax professional, enrolled agent, or CPA.