What Is an EIN Number and Do You Need One?

What Is an EIN?

An Employer Identification Number (EIN), also known as a Federal Tax Identification Number or Federal Employer Identification Number (FEIN), is a unique nine-digit number assigned by the Internal Revenue Service (IRS) to business entities operating in the United States. Think of it as a Social Security Number for your business — it is used to identify your business for tax purposes and is required for most business activities.

The EIN format is XX-XXXXXXX (two digits, a hyphen, then seven digits). Once assigned, your EIN is permanent — it stays with your business for its entire lifetime and is never reused, even if the business closes. Every LLC, corporation, partnership, and non-profit organization needs its own unique EIN.

Who Needs an EIN?

The IRS requires an EIN for any business that has employees, operates as a partnership or multi-member LLC, operates as a corporation or S-Corp, files employment, excise, alcohol, tobacco, or firearms tax returns, withholds taxes on income paid to a non-resident alien, or has a Keogh plan (a type of retirement plan for self-employed individuals).

Even if you are not legally required to have an EIN, you should get one if you have an LLC or any formal business entity. Here is why: banks require an EIN to open a business bank account, many vendors and clients require a W-9 form with your EIN before doing business with you, using an EIN instead of your SSN on business documents reduces your risk of identity theft, and some states require an EIN on state tax filings.

Single-member LLCs are a common point of confusion. The IRS does not require a single-member LLC to have an EIN if it has no employees and does not file excise or pension plan tax returns. However, you will almost certainly need one to open a business bank account, and your bank will not accept your personal SSN for an LLC account. Get an EIN — it is free, takes five minutes, and you will need it.

How to Apply for an EIN

The easiest and fastest way to get an EIN is to apply online through the IRS website at irs.gov/ein. The online application is available Monday through Friday, 7 a.m. to 10 p.m. Eastern Time. The process takes about 5-10 minutes, and you receive your EIN immediately upon completion.

To complete the application, you will need the legal name of your LLC (exactly as it appears on your Articles of Organization), the responsible party's name and SSN or ITIN (the person who controls or manages the LLC), your LLC's mailing address, the date your LLC was formed, the reason for applying, the number of employees you expect to hire in the next 12 months, and your LLC's primary business activity.

The "responsible party" is the person the IRS considers to be in charge of the business. For a single-member LLC, this is you. For a multi-member LLC, this is typically the managing member. The responsible party must have a valid SSN or ITIN.

You can also apply by mail using Form SS-4 (processing takes 4-5 weeks) or by fax (processing takes about 4 business days). There is no reason to use these slower methods unless you do not have internet access. The online application is instant and free.

EIN vs SSN vs ITIN

Your EIN, SSN, and ITIN are all tax identification numbers, but they serve different purposes. Your Social Security Number (SSN) identifies you as an individual for tax purposes. It is assigned at birth (or when you become a U.S. citizen or permanent resident) and is used on your personal tax return. Your Individual Taxpayer Identification Number (ITIN) is a tax processing number issued by the IRS to individuals who are required to have a U.S. taxpayer identification number but who are not eligible for an SSN. Your Employer Identification Number (EIN) identifies your business entity for tax purposes.

Never use your SSN when your EIN should be used. On business bank accounts, W-9 forms from clients, vendor applications, business tax returns, employment tax filings, and business license applications — always use your EIN. Using your SSN on business documents exposes you to identity theft risk and makes it harder to maintain the separation between your personal and business finances.

Common EIN Questions

Can I get an EIN before my LLC is approved? No. You need your LLC to be officially formed (Articles of Organization approved by the state) before you can apply for an EIN. The IRS application asks for your LLC's formation date and legal name, which must match your state filing.

Is there a fee for an EIN? No. The IRS issues EINs completely free of charge. Be wary of third-party websites that charge fees to "help" you get an EIN — they are simply filling out the same free IRS form and charging you $50-$200 for the service. You can do it yourself in five minutes at no cost.

Can my LLC have more than one EIN? No, each LLC should have only one EIN. If you made a mistake on your application, you do not need a new EIN — you can correct the information by calling the IRS or filing the appropriate amendment form.

What if I lose my EIN? Your EIN is included in the confirmation letter (CP 575) that the IRS sends after your application is processed. If you lose this letter, you can call the IRS Business & Specialty Tax Line at 1-800-829-4933 to retrieve your EIN. You can also find your EIN on previously filed tax returns or on correspondence from the IRS.

Do I need a new EIN if I change my LLC's name or address? No. A name or address change does not require a new EIN. You notify the IRS of the change through your next tax return or by filing Form 8822-B (Change of Address or Responsible Party).

Do I need a new EIN if I add or remove LLC members? Adding or removing members does not require a new EIN for a multi-member LLC. However, if a single-member LLC adds a member and becomes a multi-member LLC, or vice versa, the tax classification changes and a new EIN may be required.

What to Do After Getting Your EIN

Once you have your EIN, take these next steps: save your EIN confirmation letter (CP 575) in a secure location — you will need it repeatedly. Open a business bank account using your EIN and Articles of Organization. Register for state and local taxes if required in your jurisdiction. If you plan to hire employees, register with your state's labor department and set up payroll. Apply for any required business licenses using your EIN. Give your EIN to clients who request a W-9 form.

Your EIN is a foundational piece of your business infrastructure. It costs nothing, takes minutes to obtain, and is required for virtually every business activity. Do not skip this step.