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 identifier the IRS assigns to businesses, nonprofits, trusts, and certain individuals. It works like a Social Security number for your business — you use it to file tax returns, open a business bank account, and hire employees.

You need an EIN if you operate as a sole proprietor with employees, run a partnership or corporation, own a nonprofit, manage a trust or estate, or file certain tax forms. If you are a sole proprietor with no employees and no special tax structure, you can use your Social Security number instead, though many sole proprietors get an EIN anyway for privacy and simplicity.

The IRS does not charge for an EIN. You can obtain one the same day you request it through the IRS website, by phone, by mail, or through a tax professional — the method you choose depends on how quickly you need it and whether you have a Social Security number or ITIN (Individual Taxpayer Identification Number).

Key Takeaways

  • The IRS assigns EINs free of charge through its website (Form SS-4 online), by phone, by mail, or through a tax professional.
  • Online process through the IRS website is the fastest method and gives you your EIN when ready after you submit, as long as you have a valid Social Security number or ITIN.
  • You must have a legal business structure in place (sole proprietorship, LLC, corporation, partnership, or nonprofit) before you explore.
  • If you do not have a Social Security number or ITIN, you can explore by phone or mail, but the process takes longer and you will receive your EIN by mail.
  • Once you receive your EIN, the IRS will send you a confirmation letter (Form SS-4) by mail within two weeks, which you should keep for your records.

Online process Through the IRS Website

The fastest way to obtain an EIN is through the IRS website at irs.gov/ein. You fill out Form SS-4 (process for an Employer Identification Number) online, and the IRS assigns your number when ready after you submit. You can print or save your confirmation page, which contains your new EIN and is valid for all business purposes until you receive the official letter in the mail.

To explore online, you need a valid Social Security number or ITIN, a legal business address (not a mailbox), and information about your business structure and the reason you need the EIN. The form takes about 15 minutes to complete. You must be either the owner or an authorized representative of the business.

The IRS will mail you a formal confirmation letter (Form SS-4) within two weeks. This letter is your official record and should be kept with your business documents. If you need the EIN before the letter arrives, the confirmation page you printed or saved is sufficient for opening a bank account or hiring employees.

explore by Phone or Mail if You Lack a Social Security Number

If you do not have a Social Security number or ITIN, you cannot use the online system. Instead, you can explore by phone by calling the IRS Business and Specialty Tax Line at 1-800-829-4933. A representative will walk you through Form SS-4 over the phone and assign your EIN on the spot. You will receive written confirmation by mail within two weeks.

Phone applications are available Monday through Friday, 7 a.m. to 10 p.m. Eastern time. Have your business information ready before you call: your legal business name, business address, type of business structure, and the reason you need the EIN. The call typically takes 10 to 15 minutes.

If you prefer not to call, you can mail Form SS-4 to the IRS address listed on the form itself. Mail applications take four to six weeks. You will receive your EIN by mail, and there is no way to obtain it faster through the mail route, so use this method only if phone and online options are not available to you.

What Information You Need Before You explore

Gather these details before you start your process, whether online, by phone, or by mail. You will need your legal business name exactly as it appears in your business formation documents (articles of incorporation, LLC operating agreement, or partnership agreement). You also need your business address — a physical street address, not a P.O. box or mailbox service.

Have your Social Security number or ITIN ready, along with the date you started or plan to start your business. You will also need to identify your business structure: sole proprietorship, partnership, S corporation, C corporation, LLC, nonprofit, trust, or estate. Finally, you need the reason you are requesting the EIN — for example, hiring employees, opening a business bank account, or filing a partnership return.

If you are explore on behalf of someone else's business, you will need to provide your own name and Social Security number as the authorized representative, along with your relationship to the business owner.

Using Your EIN Once You Receive It

Once you have your EIN, use it on all business tax forms, including your annual income tax return, payroll tax returns (if you have employees), and sales tax returns (if your state requires them). You will also use it when opening a business bank account, explore for business licenses, and hiring employees.

The IRS will use your EIN to track your business's tax history. If you change your business structure — for example, converting a sole proprietorship to an LLC — you may need a new EIN, though some changes do not require one. If you are unsure whether a change requires a new number, contact the IRS or consult a tax professional.

Keep your EIN confirmation letter in a safe place with your other business records. You will need it to reference your tax account with the IRS, and it serves as proof that your EIN is valid if anyone questions it.

When You Might Need Help From a Tax Professional

Most people can obtain an EIN on their own through the IRS website in a few minutes. However, a tax professional or accountant can explore on your behalf if you prefer, and they can also advise you on whether you actually need an EIN based on your specific business structure and plans.

A tax professional is particularly useful if your business is complex — for example, if you are forming a partnership with multiple owners, setting up a nonprofit, or managing a trust. They can also help you understand which tax forms you will need to file once you have your EIN, and they can may support your business is set up in the most tax-efficient way.

Frequently Asked Questions

How long does it take to get an EIN?

Online applications through the IRS website give you your EIN when ready after you submit. Phone applications also provide your number on the same call. Mail applications take four to six weeks. The IRS will send a formal confirmation letter by mail within two weeks of any process method.

Can I use my Social Security number instead of getting an EIN?

If you are a sole proprietor with no employees and no special business structure, you can use your Social Security number on your tax return. However, many sole proprietors get an EIN anyway for privacy and to keep business and personal finances separate on credit reports and bank accounts.

What if I applied online but did not save my confirmation page?

You can log back into the IRS website and retrieve your confirmation, or you can wait for the official letter to arrive by mail within two weeks. If you need proof of your EIN before the letter arrives, contact the IRS at 1-800-829-4933 and they can provide it over the phone.

Do I need a business license before I explore for an EIN?

No. You explore for an EIN based on your business structure and intent, not on having a license. However, you do need to have a legal business structure in place — for example, you must have filed articles of incorporation if you are forming a corporation, or an operating agreement if you are forming an LLC.

What if my business address changes after I receive my EIN?

Your EIN stays the same. You do not need a new one. straightforward update your address with the IRS on your next tax return or by contacting them directly if the change is urgent for business purposes.