skip to Main Content
2018 Tax Deadlines

2018 Tax Filing Dates and Important Deadlines for Colorado

You know what they say – death and taxes are the only two things guaranteed in life. Like it or not, no one is exempt from taxes, but on the bright side, your team at Yeater & Associates is here to help keep you on track so you can worry about the more important things in life.

Today, we’d like to put out a friendly reminder of important 2018 Colorado tax filing dates and deadlines to keep you from getting behind schedule.

2018 Income Tax Filing Deadlines

First off, let’s start with the basics that should be on everyone’s radar:

April 17, 2018 – Income tax filing deadline for 2017 Colorado State Tax Returns

Keep in mind the usual deadline for individuals and corporations filing income tax returns is April 15. For calendar year companies, this date typically is on or around Emancipation Day, which can impact the deadline. (Emancipation Day is April 16, but the government recognizes it on a Friday if that day happens to fall on a Saturday, or Monday if it lands on a Sunday.)

April 17, 2018 – Due date for Colorado automatic tax extensions

This date also serves as the deadline for the automatic tax extension. In Colorado, taxpayers do not have to fill out a form to receive this extension; it is automatically granted to them and they will only be responsible for interest fees.

Oct. 15, 2018 – Deadline for Colorado tax extension

Mark your calendars, because this date is right around the corner! The extended due date for corporate and individual taxes will be October 15, 2018. This is the final date for extension filers or e-filers to pay income taxes in Colorado.

When are business taxes due in 2018 (for 2017 tax filing)? 

FORM                                                                        2018 Filing Due Date

Form 1065 – Partnerships

Form 1120S – S Corporations

Form 1040 – Individuals

FinCEN 114 – FBAR

March 15th

March 15th

April 17th

April 17th

Form 1041 – Trusts and Estates

Form 1120 – C Corporations

Form 990 Series – Tax Exempt Org

Form 5500 Series – Employee Benefit Plan


April 17th

April 17th

May 15th

July 31st

Quarterly Tax Paying Deadlines for Individuals and Corporations

If you are self-employed or have other quarterly income that requires you to pay quarterly estimated taxes, get them postmarked by these tax deadlines below.


  • 1st Quarter2018 Estimated Tax Payment Due: April 17, 2018
  • 2nd Quarter 2018 Estimated Tax Payment Due: June 15, 2018
  • 3rd Quarter 2018 Estimated Tax Payment Due: Sept. 17, 2018
  • 4th Quarter 2018 Estimated Tax Payment Due: Jan. 15, 2019


Additional Form Deadlines

In addition to these general tax dates, there are several ongoing dates employees and employers alike need to pay attention to.

Approximately the second Monday of each month:

Employees who work for tips – and have made more than $20 in tips – need to report the tip amount to their employer using Form 4070.

Approximately the 15th of each month:

Deadline for employers to pay social security, Medicare and withheld income tax for the previous month.

These tax filing deadlines are just to get you started, but to ensure that you have all your bases covered for individual and business taxes, we recommend meeting with our qualified accountants to go through each and every deadline that specifically applies to you. Give Yeater & Associates, CPAS a call at 970-378-4830 to get started.


Back To Top