2027 Colorado Tax Deadlines
Colorado Individual income tax filing deadlines and extensions for 2027
Colorado tax deadlines are easier to manage when the filing calendar, payment rules, and extension rules sit in one place. Tax year 2027 returns are generally filed in 2028, while estimated payments run through 2027. Use the key dates above as the single source for Colorado due dates, then apply the rules by entity type.
These dates apply to calendar-year filers. Fiscal-year filers follow different due dates tied to their fiscal year and should confirm the applicable state deadline before filing or paying.
Last updated: July 29, 2026
Key Colorado tax dates at a glance
This block is the single date reference for 2027 Colorado filing, payment, and extension planning.
- April 15, 2027: First Colorado estimated tax payment.
- June 15, 2027: Second Colorado estimated tax payment.
- September 15, 2027: Third Colorado estimated tax payment.
- January 18, 2028: Fourth Colorado estimated tax payment.
- April 18, 2028: Colorado Individual, S Corporation, and Partnership returns and payments due.
- May 15, 2028: Colorado C Corporation return and payment due.
- October 16, 2028: Extended Colorado Individual, S Corporation, and Partnership returns due, file only.
- November 15, 2028: Extended Colorado C Corporation returns due, file only.
When are Colorado taxes due in 2027?
Colorado's 2027 calendar-year Individual, S Corporation, and Partnership returns are generally due April 18, 2028, while C Corporation returns are due May 15, 2028. Estimated payments and filing-only extensions should be tracked separately by taxpayer type.
When is the Colorado C Corporation return due?
Colorado C Corporations file and pay Colorado corporate income tax by May 15, 2028. The approved 2027 draft uses Form DR 0112 for the calendar-year C Corporation filing.
- Complete Form DR 0112.
- File electronically through Revenue Online or approved software where available.
- Pay by the original due date of May 15, 2028.
- Postmark any mailed return by the due date if paper filing is allowed.
What are the Colorado C Corporation extension rules?
The extended Colorado C Corporation filing deadline is November 15, 2028. The extension is to file only; payment remains due on May 15, 2028.
When are Colorado S Corporation and Partnership returns due?
Colorado S Corporations and Partnerships file their state pass-through returns by April 18, 2028. Payment also remains tied to the original Colorado due date.
Which Colorado pass-through forms are required?
- Form DR 0106: Colorado Partnership and S Corporation Return.
- Form DR 0106K: Colorado K-1 for partners and shareholders.
What are the Colorado pass-through extension rules?
The extended Colorado S Corporation and Partnership filing deadline is October 16, 2028. The extension is to file only; payment remains due on April 18, 2028.
When is the Colorado Individual income tax return due?
Colorado Individuals file and pay their Individual income tax returns by April 18, 2028. The approved 2027 draft uses the Colorado resident and nonresident forms listed below.
Which Colorado Individual forms are commonly used?
- Form DR 0104: Colorado Individual Income Tax Return.
What are the Colorado Individual extension rules?
The extended Colorado Individual filing deadline is October 16, 2028. The extension is to file only; payment remains due on April 18, 2028.
When are Colorado estimated tax payments due?
Colorado estimated-payment planning generally centers on paying enough tax during the year to satisfy the state's 90% payment requirement and avoid underpayment penalties.
- April 15, 2027: First Colorado estimated tax payment.
- June 15, 2027: Second Colorado estimated tax payment.
- September 15, 2027: Third Colorado estimated tax payment.
- January 18, 2028: Fourth Colorado estimated tax payment.
What Colorado rules should tax professionals watch in 2027?
Beyond the core due dates, Colorado has a few state-specific mechanics that matter for 2027 filing controls:
Why is Colorado's C Corporation deadline later?
Colorado moved C Corporation returns to the 15th day of the fifth month for tax years beginning on or after January 1, 2024, for calendar-year 2027 C Corporations; that makes the original Colorado due date May 15, 2028.
How should teams handle Colorado's flat rate?
The approved draft uses current Colorado DOR guidance showing a 4.4% income tax rate. Reconfirm the 2027 rate when Colorado publishes form-year materials.
What Colorado rules can affect planning?
Colorado's TABOR refund mechanics, enterprise-zone incentives, and Revenue Online payment workflows can affect year-end planning even though the state uses a flat-rate income tax system.
Tax-professional context: Several key considerations make Colorado's tax landscape unique for 2027. Colorado's flat income tax system provides simplicity and predictability for taxpayers and tax professionals. Electronic filing requirements continue to expand, and Colorado offers various tax planning opportunities.
Electronic filing requirements:
- C Corporations and pass-through entities should file electronically through Revenue Online.
- Individuals can use Colorado online filing where available.
- Business deductions can be processed more efficiently through electronic systems.
- Professional preparers must use approved software vendors.
Flat-rate Colorado income tax; current DOR guidance lists 4.4% for 2025: Colorado's flat tax structure provides simplicity and predictability for all taxpayers.
90% payment requirement to avoid underpayment penalties: Colorado requires taxpayers to pay 90% of their estimated tax liability to avoid penalties.
TABOR and Revenue Limitations:
- Constitutional revenue limitations may trigger refunds to taxpayers.
- TABOR refunds are distributed when state revenues exceed limits.
- Tax planning must consider potential refund mechanisms.
- Multi-year planning is affected by revenue limitations.
Business incentives and credits:
- Enterprise zone credits for qualifying businesses.
- Job growth incentive tax credits.
- Research and development credits.
- Advanced industry investment tax credits.
Retirement income considerations:
- Military retirement pay exemptions may apply.
- Social Security benefits treatment.
- Pension income considerations for residents.
Which sources were used for this Colorado deadline guide?
- Colorado Corporate Income Tax Guide.
- Colorado Individual Income Tax Guide.
- Colorado Tax Profile and Expenditure Report.
- Colorado Enterprise Zone Tax Guide.
Colorado tax calendar for estimates and TABOR rules
Colorado teams have to manage flat income-tax rules, corporate and pass-through due dates, estimated payments, and local add-on obligations in the same filing season. Instead's AI-driven tax platform keeps those facts attached to the return workflow.
Use filing to move Colorado returns forward, research to verify state-specific rules, and multi-entity tools for groups with Colorado and non-Colorado entities. Built for tax professionals who want a better tax operation system to manage compliance and advisory work for clients.
The material discussed on this page is meant for general illustration and/or informational purposes only and is not to be construed as investment, tax, or legal advice. You must exercise your own independent professional judgment, recognizing that advice should not be based on unreasonable factual or legal assumptions or unreasonably rely upon representations of the client or others. Further, any advice you provide in connection with tax return preparation must comply in full with the requirements of IRS Circular 230.
Please note that if any due date falls on a federal or state holiday or weekend, it may be adjusted to the next business day. Always verify current deadlines with the appropriate tax professional and authorities.
Looking for a different year?
.png){kind=small}