What a Federal Tax ID Number Is and Who Needs One

A Federal Tax ID Number, also called an Employer Identification Number (EIN), is a nine-digit code the IRS uses to identify your business or organization for tax purposes. The IRS issues it free, and you do not pay a fee to obtain one.

You need an EIN if you operate a business as a sole proprietor with employees, run a partnership, own a corporation or LLC, operate a nonprofit organization, or file certain tax forms. If you are self-employed with no employees and file taxes under your Social Security number, you may not need one — but many self-employed people get one anyway to keep business and personal finances separate on tax records.

The number stays with your business for its lifetime. If your business closes, the EIN does not transfer to a new business; you would need to request a new one.

Key Takeaways

  • You can request an EIN online through the IRS website at no cost, and you receive the number immediately after your application is processed.
  • The online application takes about 15 minutes and requires basic information about your business structure, ownership, and what your business does.
  • If you cannot use the online system, you can mail Form SS-4 to the IRS or fax it, though these routes take two to four weeks for processing.
  • You need your Social Security number or Individual Taxpayer Identification Number (ITIN), your business address, and information about your business structure before you start.
  • The EIN is free; any website charging a fee to obtain one is not an official government source.

How to Request an EIN Online

The fastest way to get an EIN is through the IRS website at irs.gov/ein. Go to the "Apply for an EIN Online" section. You will answer questions about your business structure (sole proprietor, partnership, S corporation, nonprofit, etc.), the type of business you operate, and who owns it. The form takes about 15 minutes to complete.

You will need your Social Security number or ITIN, your business address, the mailing address if different, and the date you started or plan to start your business. Have the names and Social Security numbers of all owners ready if your business is a partnership or LLC with multiple members.

After you submit, the system processes your application immediately. You receive your EIN on screen right away and can print a confirmation page. The IRS also emails a copy to the address you provide. You can use the number immediately for tax purposes, opening a business bank account, or hiring employees.

Mailing or Faxing Form SS-4 If You Cannot Go Online

If you do not have internet access or cannot use the online system, you can request an EIN by mail or fax using Form SS-4 (Application for Employer Identification Number). You can download the form from irs.gov or call the IRS at 1-800-829-4933 to request a copy by mail.

Fill out the form with your name, business name, business address, Social Security number or ITIN, and information about your business structure and what you do. Mail it to the IRS address listed on the form instructions, or fax it to the fax number provided. Processing takes two to four weeks by mail and one to two weeks by fax.

When you mail or fax the form, include a cover sheet with your phone number and email address so the IRS can contact you if they need more information. Keep a copy for your records.

What Information You Need Before You Apply

Gather these items before you start your application, whether online, by mail, or by fax:

  • Your Social Security number or ITIN
  • Your legal business name and any trade names or "doing business as" names
  • Your business address (street, city, state, ZIP code)
  • The date you started or plan to start your business
  • Your business structure (sole proprietor, partnership, corporation, LLC, nonprofit, trust, etc.)
  • A description of what your business does
  • If you have a business partner or co-owner, their name and Social Security number or ITIN
  • Your phone number and email address

If you are applying on behalf of a business you do not own — for example, if you are a representative or officer — you will also need to provide your name, title, and relationship to the business.

After You Receive Your EIN

Once you have your EIN, use it on all business tax forms, business bank account applications, and when you hire employees. The IRS links all your business tax filings to this number, so it is important to use the same EIN consistently.

Keep your EIN confirmation letter in a safe place. You will need it when you open a business bank account, file your first tax return, or apply for business licenses or permits. Some banks and government agencies ask to see proof that the EIN is valid, and your confirmation letter serves that purpose.

If you lose your EIN or cannot find your confirmation letter, you can look it up on the IRS website or call 1-800-829-4933. Have your business name, address, and Social Security number ready when you call.

EIN vs. Social Security Number for Business Taxes

As a sole proprietor with no employees, you can file business taxes using your Social Security number instead of an EIN. Many small business owners do this. However, using an EIN instead has advantages: it keeps your personal and business finances separate on IRS records, it is easier to hire employees or contractors later, and it looks more professional to banks and vendors.

If you start as a sole proprietor using your Social Security number and later hire employees or change your business structure, you will need to obtain an EIN at that time. There is no penalty for getting an EIN early or for not having one if you do not need one.

Common Mistakes to Avoid

Do not pay a fee to obtain an EIN. The IRS issues EINs free through irs.gov. Websites that charge $50, $100, or more to "help" you get an EIN are not official government sources. They may fill out the form for you, but you are paying for a service the IRS provides at no cost.

Do not confuse your EIN with your Social Security number when filing taxes. Use your EIN on all business tax forms and your Social Security number on personal tax forms. If you mix them up, the IRS may delay processing your return or send you a notice asking for clarification.

Do not apply for multiple EINs for the same business. Each business gets one EIN for life. If you apply twice by mistake, contact the IRS to close the duplicate number so you do not file taxes under two different EINs.

Frequently Asked Questions

How long does it take to get an EIN?

Online applications are processed immediately, and you receive your number on screen and by email the same day. Mailed applications take two to four weeks, and faxed applications take one to two weeks. If you need the number urgently, apply online.

Can I get an EIN if I do not have a Social Security number?

You need either a Social Security number or an Individual Taxpayer Identification Number (ITIN) to request an EIN. If you do not have either, you will need to obtain an ITIN first through the IRS before you can apply for an EIN.

Do I need an EIN if I am a sole proprietor with no employees?

No, you can file business taxes using your Social Security number. However, many sole proprietors get an EIN anyway to separate business and personal finances on tax records and to look more professional to banks and clients.

What if I made a mistake on my EIN application?

If you submitted the application online and realized a mistake before you received your number, contact the IRS immediately at 1-800-829-4933. If you already received your EIN and need to correct information, call the IRS to update your business records.

Can I use my EIN right away, or do I have to wait for a confirmation letter?

You can use your EIN immediately after you receive it online or by email. You do not have to wait for a printed confirmation letter to arrive by mail. Keep the email or printed confirmation for your records.