Direct Answer

An EIN (Employer Identification Number) is a 9-digit number the IRS assigns to identify your LLC for federal tax purposes. Multi-member LLCs, LLCs with employees, and LLCs electing corporate taxation are legally required to have one. Single-member LLCs without employees may not be legally required to get one — but banks, payroll services, and clients typically require it. Applying is free at IRS.gov. The exact requirement depends on your LLC's tax classification and state.

What Is an EIN?

An EIN — Employer Identification Number — is a unique 9-digit number formatted as XX-XXXXXXX. The IRS issues it to identify your business entity for federal tax purposes. Think of it as a Social Security Number for your company.

The EIN is also called a:

  • Federal Tax ID Number (FTIN)
  • Federal Employer Identification Number (FEIN)
  • Taxpayer Identification Number (TIN) (in some business contexts)

An EIN is used to:

  • File federal business tax returns
  • Open a business bank account
  • Hire and pay employees (payroll)
  • Complete Form W-9 for clients and vendors
  • Apply for business credit
  • Register for state tax accounts

Your EIN stays with your LLC permanently unless the underlying entity structure changes significantly.

When Does an LLC Need an EIN?

Whether an LLC is legally required to have an EIN depends on its tax classification, structure, and activities.

LLCs That Are Required to Have an EIN

LLC Type Reason EIN Is Required
Multi-member LLC (default partnership) Files Form 1065 as a partnership. Partnerships must have an EIN.
LLC with employees (any type) Must withhold and remit payroll taxes to the IRS. Payroll requires an EIN.
LLC taxed as S-Corporation Electing S-corp status creates a separate taxpaying entity. Requires an EIN and files Form 1120-S.
LLC taxed as C-Corporation C-corps file their own return (Form 1120) and require an EIN.
LLC that pays excise taxes Certain industries (fuel, alcohol, tobacco) trigger mandatory EIN requirements.
LLC with a Keogh plan Retirement plan administration requires an EIN.

LLCs Where an EIN Is Practically — but Not Legally — Required

A single-member LLC that is a disregarded entity with no employees is not legally required to have a federal EIN. The owner may use their personal SSN on their Schedule C. However, in practice, this is rarely workable:

  • Banks: Most U.S. banks require an EIN to open a business checking account in the LLC's name.
  • Clients: When clients ask for a W-9, putting your SSN on it exposes your personal identification number to potentially dozens of businesses.
  • Vendors: Many payment processors, software platforms, and wholesale vendors require an EIN for business accounts.
  • Payroll services: If you ever hire even one contractor or employee, you will need an EIN.
Rule of Thumb

If you have an LLC, get an EIN. It's free, takes 15 minutes, and prevents you from handing your Social Security Number to every client you work with. There is no practical downside.

Single-Member LLC and EIN

A single-member LLC is treated as a disregarded entity by the IRS by default. This means the IRS ignores the LLC's existence as a separate taxpayer and treats the income as belonging directly to the owner. The owner reports business income on Schedule C of their personal tax return (Form 1040).

Because the IRS treats a disregarded entity's tax identity as the owner's personal identity, the owner's SSN is technically acceptable for federal tax purposes. But the EIN is still needed in real-world business operation.

Key situations where a single-member LLC needs its own EIN:

  • Opening a business bank account
  • Applying for a business credit card
  • Completing Form W-9 with an EIN instead of SSN
  • Hiring any employee (even one part-time employee)
  • Electing to be taxed as an S-corporation
  • Protecting SSN privacy when working with multiple clients

→ See the full guide: EIN for Single-Member LLC: When You Need One and When You Don't

Multi-Member LLC and EIN

A multi-member LLC is treated as a partnership by the IRS by default. Partnerships are required to file Form 1065 (U.S. Return of Partnership Income) and issue Schedule K-1 forms to each member showing their share of income, deductions, and credits.

Partnerships must have an EIN. There is no workaround — a multi-member LLC cannot file Form 1065 without one.

Additional reasons multi-member LLCs require an EIN:

  • Form 1065 filing requirement
  • K-1 issuance to each member
  • Business bank account in the LLC's name
  • Any payroll obligations

→ See the full guide: EIN for Multi-Member LLC: What Owners Need to Know

EIN vs SSN: Which to Use?

This is one of the most common questions LLC owners have. The answer depends on what you're using the tax ID number for and what type of LLC you have.

Situation Use SSN? Use EIN? Notes
Single-member LLC, no employees, Schedule C filer ✓ Allowed ✓ Preferred EIN recommended for privacy and banking
Multi-member LLC (partnership) ✗ Not applicable ✓ Required Partnership must have EIN for Form 1065
LLC taxed as S-corp ✗ Not applicable ✓ Required Separate entity for tax; files Form 1120-S
LLC with employees ✗ Not applicable ✓ Required Payroll tax remittance requires EIN
Form W-9 for single-member LLC ✓ Allowed ✓ Preferred Check IRS W-9 instructions for disregarded entities
Opening a business bank account ✗ Usually rejected ✓ Required Most banks require EIN for LLC accounts

How to Apply for an EIN for Your LLC

The IRS provides four ways to apply for an EIN:

Method Eligibility Processing Time Cost
Online (IRS.gov) U.S.-based applicants with SSN or ITIN only Immediate Free
Fax (Form SS-4) Any applicant; required for foreign founders without SSN/ITIN 4 business days Free
Mail (Form SS-4) Any applicant 4–5 weeks Free
Phone (international) Non-U.S. applicants without fax access Immediate (during call) Free

Steps to Apply Online

  1. Go to IRS.gov: Navigate to the EIN Online Application page. Confirm you are on a .gov domain.
  2. Click "Apply Online Now": The online system is available Monday–Friday, 7 AM to 10 PM Eastern Time.
  3. Select your entity type: Choose "Limited Liability Company (LLC)" from the entity type menu.
  4. Answer the application questions: You'll provide the number of LLC members, the reason for applying, and contact information. The "responsible party" must be an individual (not another entity).
  5. Review and submit: Review your information and submit the form.
  6. Download your EIN confirmation: Your EIN is issued immediately. Download and save the official IRS EIN Confirmation Letter (CP 575). This letter is your proof of EIN assignment.
Watch Out for EIN Scams

Searching "apply for EIN" online often returns paid third-party services in the top ad positions that charge $50–$300 to submit an IRS application on your behalf. The IRS application is 100% free. Always verify you are on a .gov address before entering any information.

→ Full step-by-step guide: How to Apply for an EIN for an LLC

EIN and Form W-9

Form W-9 is the IRS form that U.S. businesses and contractors use to provide their Tax Identification Number to a payer. When a client hires you and needs to issue a 1099 at year end, they will ask for your completed W-9.

How your LLC fills out a W-9 depends on its tax classification:

  • Single-member LLC (disregarded entity): Line 1 = owner's legal name; Line 2 = LLC name; check "Individual/sole proprietor or single-member LLC"; use SSN or EIN in Part I.
  • Multi-member LLC (partnership): Line 1 = LLC name; check "Partnership"; use LLC's EIN in Part I.
  • LLC taxed as S-corp: Line 1 = LLC name; check "S Corporation"; use LLC's EIN in Part I.

→ Full W-9 guide for LLCs: W-9 for LLC: How to Fill Out Form W-9 Based on Tax Classification

→ EIN vs SSN on W-9: W-9 for LLC: Should You Use an EIN or SSN?

EIN and Business Banking

Maintaining a separate business bank account is one of the most important steps for LLC owners to protect their personal liability shield. Mixing personal and business finances can lead to "piercing the corporate veil," which can eliminate the liability protection an LLC provides.

Almost every U.S. bank requires your LLC's EIN to open a business checking account. Banks that commonly require an EIN for LLC accounts include:

  • Chase Business Banking
  • Bank of America Business
  • Wells Fargo Business
  • Mercury (online business bank popular with startups)
  • Bluevine
  • Relay Financial

You will typically need to bring your EIN confirmation letter (or the EIN number itself) along with your LLC's Articles of Organization or Certificate of Formation when opening the account.

Common EIN Mistakes to Avoid

Common Mistakes
  • Paying for an EIN: The IRS application is free. Never pay a third party to get you one unless you are a foreign founder who genuinely needs faxing or mail-in services.
  • Getting an EIN before forming the LLC: Your LLC must legally exist before applying for its EIN. Form the LLC first with your state Secretary of State, then apply for the EIN.
  • Using the wrong entity type on the application: Select "Limited Liability Company" — not Sole Proprietor or Partnership — when completing the IRS online form.
  • Losing your EIN confirmation letter: The CP 575 letter from the IRS is your official proof. Save it. You can call the IRS to get your EIN if you lose it, but you cannot get a replacement CP 575.
  • Assuming you need a new EIN when you don't: Changing your LLC's name, address, or adding members does not automatically require a new EIN. However, converting an LLC to a corporation or certain structural changes may require a new one.
  • Applying for multiple EINs for the same LLC: Each LLC gets one EIN. Applying multiple times for the same entity can create IRS record-keeping issues.

EIN and LLC Tax Forms

Your EIN determines which federal tax forms your LLC files. Here is a summary:

LLC Tax Classification Federal Tax Form Filing Deadline EIN Required?
Single-member LLC (disregarded entity) Schedule C (Form 1040) April 15 Recommended
Multi-member LLC (partnership) Form 1065 + K-1s March 15 Yes — required
LLC taxed as S-Corp Form 1120-S + K-1s March 15 Yes — required
LLC taxed as C-Corp Form 1120 April 15 Yes — required

→ See the full tax forms guide: LLC Tax Forms: What Forms Does an LLC File?

EIN Checklist for LLC Owners

Before You Apply
  • [ ] LLC is fully formed and registered with your state (Articles of Organization filed and approved)
  • [ ] You have your LLC's legal name exactly as registered with the state
  • [ ] You know the number of LLC members
  • [ ] You know the LLC's principal business activity
  • [ ] The responsible party (applicant) has an SSN or ITIN
  • [ ] You are applying on IRS.gov — not a third-party site
After You Get Your EIN
  • [ ] Download and save the IRS EIN Confirmation Letter (CP 575)
  • [ ] Store the EIN in a secure location accessible to all LLC members
  • [ ] Open a business bank account with your EIN
  • [ ] Register for any required state tax accounts (sales tax, payroll, etc.)
  • [ ] Update your W-9 template with the correct EIN
  • [ ] Notify your accountant or bookkeeper of the EIN