EIN for Your Connecticut LLC — How to Apply
An Employer Identification Number is your LLC's federal tax ID. After filing your Certificate of Organization, apply for an EIN at irs.gov — it's free and immediate online. For formation, see our LLC guide.
Why Your CT LLC Needs an EIN
- Business bank accounts (CT banks require it)
- CT Department of Revenue Services registration (sales tax, withholding)
- Hiring employees in Connecticut
- W-9 forms for clients (use EIN, not SSN)
- The CT PET election requires entity-level tax filings with an EIN
How to Apply
Online (recommended): irs.gov — immediate issuance, Mon-Fri 7am-10pm ET Fax: Form SS-4 — 4 business days Mail: Form SS-4 — 4-6 weeks
After Receiving Your EIN
Ready to get started?
Get Started- Open CT business bank account (Webster Bank, M&T, Liberty Bank, etc.)
- Register with CT DRS (portal.ct.gov/DRS) for sales tax and/or withholding
- Update W-9 forms — give clients your EIN, not SSN
- Save CP 575 confirmation letter
CT-Specific Registrations After EIN
| Registration | When | Agency |
|---|---|---|
| Sales Tax Permit | If selling taxable goods/services | CT DRS |
| Withholding | If you have CT employees | CT DRS |
| Unemployment | If you have employees | CT Department of Labor |
FAQ
Can I apply before my LLC is approved?
No. Wait for Secretary of State confirmation that your Certificate of Organization was filed.
Do I need a new EIN if I elect PET or S-corp?
No. Tax elections don't require new EINs. The same EIN is used for all filings regardless of election.