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IRS fee
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Non-US founders
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State tax ID
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Connecticut EIN application, 2026
EIN in Connecticut · same-day SS-4

Get an EIN for your Connecticut business

A federal Employer Identification Number (EIN) is the IRS tax ID your Connecticut business uses for banking, payroll, and tax filing. The IRS issues EINs free · application takes 10 minutes online with immediate issuance for US founders. International founders apply by fax or mail. After your EIN, you also need to register with the Connecticut Department of Revenue Services via the REG-1 Business Tax Registration.

Connecticut EIN + state tax accounts at a glance

Federal EIN cost$0 (IRS direct)
Issuance timeImmediate (online for US founders)
Connecticut revenue agencyConnecticut Department of Revenue Services
State tax registration formREG-1 Business Tax Registration
Sales tax permit needed?Yes · register for sales tax permit.
State withholding account?Yes · register for state withholding account.
File.Business service fee$0

How to get an EIN in Connecticut: step by step

  1. Form your business entity first. Your Connecticut LLC, corporation, or other entity must exist before applying for an EIN. Form an LLC in Connecticut or form a corporation if needed.
  2. Pick your responsible party. The IRS requires one individual with substantial control over the entity (typically an owner with at least 25% interest) to be listed on Form SS-4.
  3. Apply online at irs.gov. US founders with a valid SSN or ITIN get the EIN immediately. The application is free and takes about 10 minutes.
  4. International founders: apply by fax or mail. Without an SSN or ITIN, the online system will not work. Fax Form SS-4 (typically 4 business days) or mail it (4 to 6 weeks). ITIN vs EIN explained.
  5. Register with the Connecticut Department of Revenue Services. Use the REG-1 Business Tax Registration to get your state-level tax accounts in Connecticut.
  6. Open a business bank account. Connecticut banks commonly used include Webster Bank, Peoples United, Bank of America.

Skip the paperwork · we get your Connecticut EIN

We prepare Form SS-4, file with the IRS, and also handle your state-level registration with the Connecticut Department of Revenue Services. $0 service fee. International founders supported (we file by fax to get your EIN within a week, faster than mail).

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Connecticut state tax accounts you also need

An IRS EIN is federal-only. To operate in Connecticut, you typically also need:

  • State tax ID: Register with Connecticut Department of Revenue Services using REG-1 Business Tax Registration.
  • Sales tax permit: Yes · register for sales tax permit. Sales tax registration overview.
  • State withholding account: Yes · register for state withholding account.
  • Unemployment insurance account: Required if you have employees in Connecticut.
  • Workers compensation insurance: Required if you have employees. Business insurance overview.

Connecticut EIN FAQ

How much does an EIN cost in Connecticut?

The IRS issues EINs free. Anyone charging you for the EIN itself is upselling. File.Business charges $0 service fee whether you have us file it or you do it yourself.

How long does the EIN take to receive?

US founders applying online: immediate. International founders applying by fax: typically 4 business days. By mail: 4 to 6 weeks.

Can I get an EIN without an SSN?

Yes. International founders apply with Form SS-4 by fax or mail. The IRS accepts foreign passport details as identification.

Do I need a separate Connecticut state tax ID?

Yes, in most cases. The Connecticut Department of Revenue Services requires a state-level registration via REG-1 Business Tax Registration for businesses operating in Connecticut.

Can I use my EIN to open a Connecticut business bank account?

Yes, your EIN is required for business banking. Connecticut banks commonly used include Webster Bank, Peoples United, Bank of America.

$129/yr Compliance Annual Filings · penalty-free

On the $129/yr Compliance Annual Filings plan, we cover state late fees.

When you autofile your annual report through the $129/yr plan and we miss the deadline, we pay the state's late fee. The guarantee applies to that specific plan and the filings it includes. Other File.Business services are billed at the prices on this page.

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File.Business is a private business filing and compliance service. We are not a government agency and are not affiliated with any Secretary of State office. You may file directly with the appropriate state agency. SOC 2 Type II audited. 220,000+ businesses formed since 2017.
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