Colorado state income tax
Last updated: 2026-04-27
TL;DR / ELI5
Primary form: DR 0104
BasilTax engine: Not yet — federal plus manual state review
Structure: flat
Flat state income tax; verify current rate annually.
Colorado income tax at a glance
This guide explains how Colorado fits into your overall filing picture. Your federal Form 1040 is only half the story—states add their own definitions, subtractions, credits, and withholding rules.
Most Colorado residents will prepare DR 0104 alongside the federal return. Flat state income tax; verify current rate annually.
Withholding and W-2 boxes
If you work in Colorado (or your employer withholds for Colorado), compare boxes 15–17 on your Form W-2 to what you expect on the state return. Mismatches here are a common source of balance due surprises.
Credits, deductions, and quirks
State returns often start from federal adjusted gross income (AGI) and then apply state-specific subtractions, additions, credits, and alternative minimum taxes. Read your state instructions for the exact list—this page is a hub, not a substitute for official guidance.
Verification workflow
Upload your PDFs, assign them to a return, and run compute. When BasilTax supports Colorado end-to-end, you can trace state lines to the same documents you used for federal. When support is still in progress, use BasilTax to lock down federal and broker schedules first, then complete Colorado manually with confidence.
Ready to tie every line to your documents?
Upload your W-2s and 1099s—BasilTax extracts fields, computes federal and state, and explains each number with citations.
Frequently asked questions
- Does Colorado have a state income tax?
- Yes—Colorado has a state income tax system described on DR 0104. Flat state income tax; verify current rate annually.
- What form do I file for Colorado?
- Most residents use DR 0104 for the state return, subject to exceptions for part-year residents and special situations. Always confirm the latest state instructions each filing season.
- Does BasilTax calculate Colorado state tax?
- BasilTax is focused on federal accuracy for Colorado today; you should still review state-specific rules and forms outside the app until engine support ships.