What is an EIN? Your LLC Tax ID Explained

An EIN (Employer Identification Number) is a 9-digit number assigned by the IRS to identify your business for tax purposes. Think of it as a Social Security Number for your LLC. Every LLC needs one to open a bank account, file taxes, and hire employees.

What is an EIN?

An EIN, or Employer Identification Number, is a unique 9-digit number the IRS assigns to businesses operating in the United States. It follows the format XX-XXXXXXX (for example, 12-3456789) and is used to identify your business on tax returns, banking documents, and government filings.

The IRS issues EINs at no cost. You may also see an EIN referred to by other names:

• Tax ID Number
• Federal Tax ID Number
• Federal Employer Identification Number (FEIN)

Regardless of the name, they all refer to the same 9-digit number. Just as individuals use a Social Security Number (SSN) to identify themselves to the IRS, businesses use an EIN. Your LLC's EIN stays the same for the life of the business, even if you change your business name, address, or ownership structure.

Who Needs an EIN?

The short answer: every LLC should have one. While the IRS only technically requires an EIN in certain situations, most LLCs need one in practice. Here are the most common cases:

• Every LLC (including single-member LLCs) should get an EIN to separate personal and business tax reporting
• Businesses with employees must have an EIN for payroll tax reporting
• Businesses opening a US bank account will be asked for an EIN by nearly every bank
• Businesses filing federal tax returns use the EIN to identify the entity
• Businesses applying for business licenses typically need an EIN on the application
• Businesses that withhold taxes on payments to contractors or non-resident aliens

Even if your single-member LLC has no employees, getting an EIN is strongly recommended. It protects your SSN from being shared with banks, clients, and vendors. It also establishes your LLC as a separate entity, which supports your liability protection.

EIN vs SSN vs ITIN

The IRS uses three different identification numbers, each for a different purpose. Here is how they compare:

An important distinction: you do not need an SSN or ITIN to get an EIN for your LLC. The EIN belongs to the business entity, not to you personally. International founders without an SSN can still obtain an EIN by applying through fax or mail.

How to Get an EIN

There are three ways to apply for an EIN. The best method depends on whether you have an SSN or ITIN and how quickly you need the number.

Method 1: Online (Immediate)

The fastest option. If you have an SSN or ITIN, you can apply online at IRS.gov and receive your EIN immediately upon completion. The online application is available Monday through Friday, 7 AM to 10 PM Eastern Time.

1. Go to the IRS EIN Assistant on IRS.gov
2. Select "Limited Liability Company" as the entity type
3. Enter your LLC name, state of formation, and formation date
4. Provide the responsible party's name and SSN or ITIN
5. Submit and receive your EIN immediately on screen

This method is only available to applicants with a US-based SSN or ITIN. International founders without either must use fax or mail.

Method 2: By Fax (4-7 Business Days)

Complete IRS Form SS-4 and fax it to the appropriate IRS fax number. Include a return fax number where the IRS can send your EIN. This is the fastest option for international applicants without an SSN. Most applicants receive their EIN within 4-7 business days, though some report same-day responses.

Method 3: By Mail (4-6 Weeks)

Mail your completed Form SS-4 to the IRS. Processing takes 4-6 weeks. This is the slowest method and is generally not recommended unless fax is unavailable. The IRS will mail your EIN confirmation letter to the address on the form.

How Long Does It Take?

The timeline depends on which application method you use:

• Online: Immediate. You receive your EIN as soon as you complete the application. Only available with an SSN or ITIN.
• Fax: 4-7 business days. Some applicants receive a response the same day, but plan for up to one week.
• Mail: 4-6 weeks. The IRS processes mail applications in the order they are received.

Once you receive your EIN, it is active immediately. However, some banks verify EINs against the IRS database, which can take up to 2 weeks to update after issuance. If a bank cannot verify a newly issued EIN, wait a few business days and try again, or bring your EIN confirmation letter as proof.

Frequently Asked Questions