Moved from Arizona to Colorado Mid-Year: Which State Tax Returns Do You File?
Answer
Arizona for the first part of the year, Colorado for the rest. Each state's part-year return reports the income received during that state's residency period and prorates the standard deduction, exemptions and credits accordingly. Keep evidence of the date you actually changed domicile.
Last verified
Part-year returns are designed so that neither state taxes the whole year. The risk is not double taxation by default; it is misassigning income received near the move date, and losing the proration on deductions and credits.
What you file
- 1Part-year return · ArizonaForm 140PY
File a Arizona part-year return covering the months you lived in Arizona. A part-year resident of Arizona reports the income received while a Arizona resident, plus any Arizona-source income received during the rest of the year, and prorates the deductions and credits to the residency period.
- 2Part-year return · ColoradoForm DR 0104 with Schedule DR 0104PN
File a Colorado part-year return covering the months you lived in Colorado. A part-year resident of Colorado reports the income received while a Colorado resident, plus any Colorado-source income received during the rest of the year, and prorates the deductions and credits to the residency period.
The two states, side by side
| Arizona | Colorado | |
|---|---|---|
| Taxes wages | Yes — graduated | Yes — flat |
| Reciprocity partners | None | None |
| Convenience rule | No | No |
| Nonresident return | Form 140NR | Form DR 0104 with Schedule DR 0104PN |
| Part-year return | Form 140PY | Form DR 0104 with Schedule DR 0104PN |
| Credit for other-state tax | Form 309 | Form DR 0104CR |
| Nonresident safe harbour | None published | None published |
| Local income tax | No | Yes |
| Revenue department | Arizona Department of Revenue | Colorado Department of Revenue — Taxation Division |
| Last verified |
The other direction
Reversing the commute does not always reverse the answer. Living in Colorado and working in Arizona gives:Two part-year returns.
Same two states, different situation
The withholding answer turns on how you are paid and where the work happens, not only on which two states are involved.
- W-2 commuter: Arizona → ColoradoBoth states — credit offsets the double tax
- Remote worker: Arizona → ColoradoHome state only
- 1099 contractor: Arizona → ColoradoHome state, plus the client state if you work there
Other Arizona pairs
Questions people actually ask
I moved from Arizona to Colorado mid-year. Do I have to file in both states?
Arizona for the first part of the year, Colorado for the rest. Each state's part-year return reports the income received during that state's residency period and prorates the standard deduction, exemptions and credits accordingly. Keep evidence of the date you actually changed domicile.
How do I split my income between Arizona and Colorado?
By when you received it, measured against the date your domicile actually changed. Income received while you were a Arizona resident belongs on the Arizona return and income received afterwards on the Colorado return, with each state prorating your deductions, exemptions and credits to its own part of the year. Keep evidence of the move date — a lease, a closing statement, a licence issue date.
How current is this?
The Arizona and Colorado rules on this page were last checked against Arizona Department of Revenue and Colorado Department of Revenue — Taxation Division on 2026-08-07. We re-check the full grid every December after state legislative sessions close, and re-check the convenience-of-the-employer states quarterly because that is where the rules move fastest.
Sources
Every fact above comes from the revenue department that publishes the rule. We do not cite secondary summaries, and we do not restate a figure we could not find at source.
- Arizona Department of Revenue — individual income taxaccessed 2026-08-07
- Colorado Department of Revenue — Taxation Division — individual income taxaccessed 2026-08-07