Connecticut sales tax permit, nexus, filing, and penalties guide.

Quick answer for ecommerce sellers.

If you sell taxable products or taxable services into Connecticut, you may need to register, collect, file, and remit Connecticut sales and use tax when you have physical presence in the state or meet Connecticut economic nexus standards. For remote sellers, Connecticut commonly looks at both sales volume and transaction count, so merchants should track Connecticut revenue and order count by measurement period.

The operational goal is simple: prove what happened during the filing period. A useful Connecticut filing packet separates direct website orders, marketplace-facilitated orders, taxable sales, exempt or resale sales, refunds, shipping charges, tax collected, and payment confirmation.

What creates Connecticut sales tax nexus?

Connecticut nexus can come from physical activity or economic activity. Physical presence can include inventory, employees, contractors, offices, warehouses, trade show activity, delivery activity, or other in-state business operations. Economic nexus can apply even when the seller has no Connecticut location.

• Physical presence: inventory, facilities, employees, agents, or other Connecticut business activity can create a collection obligation.
• Economic nexus: remote sellers should monitor Connecticut retail sales and separate transaction counts, including the $100,000 and 200 transaction framework used in Connecticut guidance and law.
• Affiliate or representative activity: in-state people or related entities can create fact-specific nexus issues that should be reviewed before filing.

For a multi-channel seller, the first report should be a channel rollup: Shopify or WooCommerce, Amazon, Walmart, Etsy, eBay, wholesale, exempt sales, refunds, and any marketplace tax collected on the seller's behalf.

How Connecticut registration fits into the workflow.

Connecticut sellers generally use myconneCT to register and manage sales and use tax accounts. Before registration, confirm the legal entity, federal EIN, responsible party, business address, sales start date, taxable product categories, payment account, and who will own the login.

Do not treat registration as a one-time admin task. Save the permit, account number, filing frequency, start date, payment method, and login owner in the same place as monthly filing workpapers. That makes handoffs much easier when the finance team, owner, or outside preparer needs to review the return.

Collection, taxable sales, and marketplace sales.

Connecticut's general sales and use tax rate is commonly listed as 6.35%, with special rates for certain categories. For ecommerce sellers, the more common issue is not memorizing the rate; it is making sure each transaction is categorized correctly before the return is prepared.

• Direct ecommerce sales: orders where the merchant is seller of record and may be responsible for collection.
• Marketplace sales: marketplace facilitator orders should be separated because the marketplace may collect and remit tax.
• Taxable services and digital items: Connecticut taxes some services and digital or electronically delivered products, so product taxability should be reviewed by category.
• Exempt or resale sales: resale and exemption documentation should be retained with the period workpapers.

Shipping and delivery charges can also matter. If your checkout exports do not clearly show product, shipping, discounts, refunds, and tax collected, the filing packet should include a reconciliation worksheet.

How to prepare a Connecticut sales tax filing packet.

A clean Connecticut filing packet helps the merchant approve the return without reopening every sales channel. The packet should connect source exports to the final return numbers and preserve enough support for notices or audit questions.

1. Export exact-period reports: pull orders, refunds, taxes, shipping, marketplace collection, and exemptions for the filing period.
2. Separate channels: do not blend direct website orders with Amazon, Walmart, Etsy, eBay, or other marketplace activity.
3. Map sales types: identify gross sales, taxable sales, deductions, exempt sales, resale sales, returns, and tax collected.
4. Reconcile to accounting: compare channel exports to payouts, payment processor summaries, and the bookkeeping file.
5. Prepare the return summary: document permit details, period, taxable amount, tax due, payment amount, reviewer, and filing date.
6. Save proof: keep myconneCT confirmation, payment receipt, source reports, and review notes together.

Many Connecticut sales and use tax returns are filed on a monthly cadence, but filing frequency can vary by account. Always follow the cadence and due date assigned by Connecticut DRS.

What happens if Connecticut filings are late or unsupported?

Late filings, late payments, missing resale certificates, unsupported exempt sales, and blended marketplace data can create notices, penalties, interest, and audit cleanup. The best defense is a repeatable packet that shows what was filed and why.

Before filing, review five things:

• Does the filing period match every source export?
• Are marketplace-collected transactions separated from direct-channel sales?
• Are refunds and discounts included in the same period logic?
• Are resale and exemption certificates saved where the return preparer can find them?
• Was the myconneCT confirmation and payment receipt saved after submission?

Connecticut sales tax FAQ.

What is Connecticut economic nexus?

Connecticut remote sellers generally monitor whether Connecticut retail sales exceed $100,000 and whether the seller has 200 or more Connecticut retail sales transactions during the relevant measurement period.

Where do Connecticut sellers file?

Connecticut sellers use myconneCT, the Department of Revenue Services online portal, for account registration, sales and use tax filing, and payment.

Do marketplace sales need to be separated?

Yes. Marketplace sales should be separated from direct ecommerce sales because marketplace facilitator collection can change what the merchant reports and reconciles.

What is the Connecticut sales tax rate?

Connecticut's general sales and use tax rate is commonly listed as 6.35%, though special rates and taxability rules may apply to certain goods and services.

Can AtomicTax help file Connecticut returns?

Yes. AtomicTax helps ecommerce merchants prepare filing-ready packets and complete standard sales tax filings for $45 per filing.

Official Connecticut resources to check.

• Connecticut DRS: myconneCT
• Connecticut DRS: Sales and use tax information
• Connecticut General Statutes: sales and use tax definitions