What is the Connecticut sales tax filing frequency?

The Connecticut Department of Revenue Services assigns your filing frequency (monthly, quarterly, or annually) based on your expected or actual sales volume.

When is Connecticut sales tax due?

Connecticut sales tax returns are due on the last day of the month following the reporting period. Monthly filers have until the end of the next month, quarterly filers have specific end-of-month deadlines, and annual filers are due January 31.

Are there any local sales taxes I need to file separately in Connecticut?

No. Connecticut has no local sales taxes. The 6.35% state rate applies uniformly statewide, and all filing is handled through the Connecticut Department of Revenue Services via myconneCT.

Do you still need to file a Connecticut sales tax return if you had no sales?

Yes. If you are registered for Connecticut sales tax, you must file a return for every assigned period, even if you had no sales or no tax due. Filing a zero return is required.

Can you file and pay Connecticut sales tax online?

Yes. Connecticut requires businesses to file and pay sales tax electronically through myconneCT at myconne.ct.gov.

How to file and pay sales tax in Connecticut in 2026

In this article

Quick facts: Filing for sales tax in Connecticut
When to file and pay Connecticut sales tax
Connecticut sales tax filing deadlines
How to prepare your Connecticut sales tax return
How to complete and file a Connecticut sales tax return
How to pay sales tax in Connecticut
What happens after filing and paying Connecticut sales tax
Late filing penalties and interest
Getting third-party help with sales tax filing
Sales tax filing in other states

If you're registered for Connecticut sales tax, you must file returns and pay any tax due according to the filing frequency assigned by the Connecticut Department of Revenue Services. This guide covers the filing and payment process for remote sellers and out-of-state businesses using myconneCT. Connecticut's due date is the last day of the month following the reporting period.

For broader information about Connecticut sales tax rules, rates, and exemptions, see the Connecticut Sales Tax Guide. For details on how to obtain a Connecticut Sales and Use Tax Permit, see the Connecticut Sales Tax Registration Guide.

Quick facts: Filing for sales tax in Connecticut

Key information about filing Connecticut sales tax returns, including filing frequency, deadlines, and payment options.

Connecticut sales tax filing requirements and deadlines
Fact	Detail
Filing frequency	Monthly, quarterly, or annually
Filing deadline	Last day of the month following the reporting period
Filing portal	myconneCT
Zero returns required	Yes

When to file and pay Connecticut sales tax

The Connecticut Department of Revenue Services will assign you a filing frequency (monthly, quarterly, or annually) after you register your business. The frequency is based on your expected tax liability.

Connecticut sales tax returns and payments are due at the same time, by the last day of the month following the end of the filing period. If the due date falls on a weekend or state holiday, the deadline shifts to the next business day.

Connecticut sales tax filing deadlines

Connecticut monthly filing due dates

Reports are due on the last day of the month following the reporting month.

Month	Filing Deadline
January	February 28/29
February	March 31
March	April 30
April	May 31
May	June 30
June	July 31
July	August 31
August	September 30
September	October 31
October	November 30
November	December 31
December	January 31

Connecticut quarterly filing due dates

Quarter	Filing Deadline
Q1 (January 1, March 31)	April 30
Q2 (April 1, June 30)	July 31
Q3 (July 1, September 30)	October 31
Q4 (October 1, December 31)	January 31

Connecticut annual filing due date

Reports for the previous calendar year are due on January 31.

Important note: Zero returns

Once you have a Connecticut Sales and Use Tax Permit, you are required to file returns for every assigned period regardless of whether any sales tax was collected. When no sales tax was collected, you must file a zero return electronically through myconneCT.

How to prepare your Connecticut sales tax return

Before working on your sales tax return, collect all sales information for the tax period.

Sales transactions

You need to know your total gross sales to Connecticut buyers and your taxable sales. Connecticut taxes digital goods and SaaS, so businesses selling software subscriptions or downloadable content must include those sales in their taxable figures.

Key reporting figures

In addition to your gross Connecticut sales, filing a return requires:

Total sales and income
Taxable sales
Non-taxable sales and exemptions
Deductions and adjustments
Total sales tax collected from customers during the filing period

Because Connecticut has no local sales taxes, you do not need to break down sales by county or municipality. The single statewide rate of 6.35% applies to all taxable sales.

How to complete and file a Connecticut sales tax return

Connecticut sales tax returns are filed electronically through myconneCT and must be reported in US dollars.

Step-by-step: file a Connecticut sales tax return

1. Collect all necessary information

Gather your sales records for the tax period. Because Connecticut uses a single statewide rate, you do not need to sort sales by location within the state, just distinguish taxable from non-taxable sales.

2. Log in and file online

Log in to myconneCT.
Navigate to your Sales and Use Tax account.
Select the filing period you want to file.
Enter your gross sales, taxable sales, exemptions, and total tax collected.
Review and submit your return.

3. Receive confirmation

After submitting, you will receive a confirmation number. Save this as your record of filing.

How to pay sales tax in Connecticut

Connecticut requires businesses to file and pay electronically through myconneCT. You can pay directly within the portal after filing your return. Accepted payment methods include:

Electronic funds transfer (EFT/ACH debit)
Credit card (fees may apply)

What happens after filing and paying Connecticut sales tax

After filing and paying, keep a copy of your return and payment confirmation for your records.

Save your filing confirmation and payment receipt
Keep records supporting the reported amounts
Continue filing according to your assigned frequency, remembering Connecticut's end-of-month due date
File a zero return for any period with no taxable sales

➡ Need help understanding Connecticut sales tax rules, rates, and nexus? See the Connecticut Sales Tax Guide

➡ Need to register for Connecticut sales tax? See the Connecticut Sales Tax Registration Guide

Late filing penalties and interest

If you miss a Connecticut sales tax filing deadline, file as soon as possible. Failure to file returns and remit collected tax on time results in penalties and interest charges that increase the longer you wait.

For current penalty rates and interest charges, refer to the Connecticut Department of Revenue Services website.

Getting third-party help with sales tax filing

Quaderno can simplify your Connecticut sales tax compliance by generating detailed tax reports and handling the filing process on your behalf. Connect your sales data and Quaderno manages the submission to the Connecticut Department of Revenue Services, ensuring timely and accurate filing.

Start your free trial now.

Sales tax filing in other states

Need help filing across multiple states?

Watch our webinar: US Sales Tax Registration & Filing Tips + AMA. Learn how international sellers register, file, and manage US sales tax compliance across multiple jurisdictions.

Note: At Quaderno we love providing helpful information and best practices about taxes, but we are not certified tax advisors. For further help, or if you are ever in doubt, please consult a professional tax advisor or the tax authorities.