Colorado tax deadlines in 2027: filing dates and estimated payments
Deadlines that fall in calendar 2027: the 2026 return and the 2027 estimated payments. Different year? See Colorado 2025 →
Colorado deadlines in 2027
| 2026 individual return due | April 15, 2027 |
|---|---|
| Extended filing deadline | October 15, 2027 |
| Payment due | April 15, 2027, extension or not |
| Final 2026 estimated payment | January 15, 2027 |
| 2027 estimated payments | April 15, 2027 · June 15, 2027 · September 15, 2027 · January 15, 2028 |
Conforms to April 15 with an automatic 6-month extension to October 15 (no form required).
Colorado estimated tax payments in 2027
Colorado estimated payments for the 2027 tax year follow the standard schedule: April 15, 2027, June 15, 2027, September 15, 2027, January 15, 2028. Confirm the current-year voucher and any state-specific threshold with the Colorado tax agency.
Source: tax.colorado.gov.
Colorado extensions
An extension moves the Colorado filing deadline to October 15, 2027. It does not move the payment date: pay what you expect to owe by April 15, 2027. Confirm with the Colorado tax agency whether the federal extension is honored automatically or a state form is required.
Federal deadlines in 2027
| 2026 Form 1040 | April 15, 2027 · extension October 15, 2027 |
|---|---|
| 2026 S-corp (1120-S) & partnership (1065) | March 15, 2027 |
| 2026 C-corp (Form 1120) | April 15, 2027 |
| 2027 federal estimated payments (1040-ES) | April 15, 2027 · June 15, 2027 · September 15, 2027 · January 18, 2028 |
Source: IRS Publication 509 and Form 1040-ES instructions, irs.gov.
Frequently asked questions
When are Colorado state taxes due in 2027?
Your 2026 Colorado individual income tax return is due April 15, 2027. If that date falls on a weekend or legal holiday, the deadline moves to the next business day. An extension moves the filing deadline to October 15, 2027, but any tax owed is still due on the original date.
When are Colorado estimated tax payments due in 2027?
Colorado estimated payments for the 2027 tax year are due April 15, 2027, June 15, 2027, September 15, 2027, January 15, 2028. The final installment for 2026 was due January 15, 2027.
Does Colorado accept the federal extension?
An extension moves the Colorado filing deadline to October 15, 2027. It does not extend the time to pay: pay what you expect to owe by April 15, 2027 to avoid penalties and interest.
Does a Colorado extension give me more time to pay?
No. An extension extends the time to file, not to pay. To avoid penalties and interest, pay what you expect to owe by April 15, 2027.
Dates are the statutory deadlines that fall in 2027 and move to the next business day when they land on a weekend or holiday. Each section links to the source it was checked against. Always confirm with the Colorado tax agency or the IRS before relying on a date. This is general information, not tax advice.