1099 Contractor in Colorado with a Delaware Client: Where Do You File?
Answer
Colorado taxes all of it; Delaware taxes only what you earn on its soil. Nothing is withheld from a 1099, so you pay Colorado quarterly. A Delaware client alone creates no Delaware filing obligation — performing services inside Delaware does, and Colorado then credits that tax.
Last verified
The client's location is the wrong thing to track. What matters is where you were sitting when you did the work — which is why a contractor's exposure to Delaware is measured in days on the ground rather than in invoices sent.
Delaware publishes no de minimis day count or dollar floor for nonresidents. Any Delaware-source wage income above the state's general filing threshold requires a nonresident return, and that threshold is reset each year — check the current figure on the Delaware Division of Revenue nonresident instructions before filing.
What you file
- 1Quarterly estimated payments · Colorado
Make quarterly estimated payments to Colorado Department of Revenue — Taxation Division on your full self-employment income — nothing is withheld from a 1099.
- 2Nonresident return · DelawareForm PIT-NON
File a Delaware nonresident return only if you performed services inside Delaware. Delaware publishes no de minimis day count or dollar floor for nonresidents. Any Delaware-source wage income above the state's general filing threshold requires a nonresident return, and that threshold is reset each year — check the current figure on the Delaware Division of Revenue nonresident instructions before filing.
- 3Resident return · ColoradoForm DR 0104CR
File the Colorado resident return last and claim the credit for any tax paid to Delaware.
The two states, side by side
| Colorado | Delaware | |
|---|---|---|
| Taxes wages | Yes — flat | Yes — graduated |
| Reciprocity partners | None | None |
| Convenience rule | No | Yes — general rule |
| Nonresident return | Form DR 0104 with Schedule DR 0104PN | Form PIT-NON |
| Credit for other-state tax | Form DR 0104CR | Schedule I (Form PIT-RES) |
| Nonresident safe harbour | None published | None published |
| Local income tax | Yes | Yes |
| Revenue department | Colorado Department of Revenue — Taxation Division | Delaware Division of Revenue |
| Last verified |
The other direction
Reversing the commute does not always reverse the answer. Living in Delaware and working in Colorado gives:Home state, plus the client state if you work there.
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: Colorado → DelawareBoth states — credit offsets the double tax
- Remote worker: Colorado → DelawareConvenience-of-the-employer rule — both states tax you
- Moved mid-year: Colorado → DelawareTwo part-year returns
Other Colorado pairs
Questions people actually ask
I live in Colorado and my client is in Delaware. Do I have to file a Delaware tax return?
Colorado taxes all of it; Delaware taxes only what you earn on its soil. Nothing is withheld from a 1099, so you pay Colorado quarterly. A Delaware client alone creates no Delaware filing obligation — performing services inside Delaware does, and Colorado then credits that tax.
Do reciprocity agreements help a 1099 contractor?
No. Every state reciprocity agreement in the country is an arrangement about wage withholding between two revenue departments, and a 1099 has no withholding to switch off. Whether Colorado and Delaware hold an agreement makes no difference to a self-employed filer — sourcing rules decide the answer instead.
How current is this?
The Colorado and Delaware rules on this page were last checked against Colorado Department of Revenue — Taxation Division and Delaware Division of Revenue 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.
- Colorado Department of Revenue — Taxation Division — individual income taxaccessed 2026-08-07
- Delaware Division of Revenue — individual income taxaccessed 2026-08-07