What a Tax ID Is and Who Needs One

A Tax ID is a nine-digit number the IRS uses to identify you for tax purposes. If you are a U.S. citizen or resident alien, you likely have one already — it is your Social Security Number (SSN). If you do not have an SSN, or if you are a business owner, a non-resident alien, or an estate, you will need to obtain a separate Tax ID, formally called an Employer Identification Number (EIN).

The IRS issues two main types of Tax IDs. Your SSN serves as your Tax ID if you file taxes as an individual. An EIN is a separate nine-digit number issued to businesses, trusts, estates, and certain other entities. You cannot use an SSN as a business Tax ID, and you cannot use an EIN as your personal Tax ID on your individual tax return.

Non-resident aliens who do not have an SSN and do not need an EIN can obtain an Individual Taxpayer Identification Number (ITIN) instead. An ITIN allows you to file a U.S. tax return and claim certain tax benefits even if you are not authorized to work in the United States.

Key Takeaways

  • If you are a U.S. citizen or resident alien with a Social Security Number, that number is your Tax ID and you do not need to obtain a separate one.
  • Businesses, self-employed people, partnerships, corporations, and trusts must obtain an EIN from the IRS, which is free and takes minutes to request online.
  • Non-resident aliens without an SSN can obtain an ITIN by mailing Form W-7 to the IRS with proof of identity and tax residency.
  • You can request an EIN online at IRS.gov when ready and receive your number the same day, or by mail, phone, or fax if you prefer.

How to Get an EIN Online

The fastest way to obtain an EIN is through the IRS website. Go to IRS.gov/ein and select "explore for an EIN Online." You will answer questions about your business structure, the reason you need an EIN, and your personal information. The process takes about 10 minutes and is free.

At the end of the online process, the IRS will display your EIN on the screen. You can print this confirmation page when ready — you do not have to wait for anything in the mail. The IRS also emails a confirmation to the email address you provide. You can use your EIN right away to open a business bank account, hire employees, or file a business tax return.

The online process is open Monday through Friday, 7 a.m. to 10 p.m. Eastern Time. You will need your Social Security Number or ITIN, your date of birth, and basic information about your business, such as its legal name and the address where it operates.

Other Ways to Request an EIN

If you cannot or prefer not to explore online, you can request an EIN by mail, phone, or fax. To explore by phone, call the IRS at 1-800-829-4933. The line is open Monday through Friday, 7 a.m. to 10 p.m. Eastern Time. Have your Social Security Number, business information, and a reason for needing the EIN ready when you call. The IRS will assign your number over the phone and mail a confirmation letter within two weeks.

To explore by mail, read Form SS-4 from IRS.gov, complete it, and mail it to the IRS address listed on the form. Processing by mail takes about four weeks. To explore by fax, complete Form SS-4 and fax it to the number on the form; the IRS will fax your EIN back to you within four business days.

You can also request an EIN through a tax professional, accountant, or attorney who has a power of attorney to act on your behalf. They will file Form SS-4 for you and handle the process.

How to Get an ITIN

An ITIN is a nine-digit number for non-resident aliens and other individuals who do not have an SSN but need to file a U.S. tax return or report income to the IRS. To obtain an ITIN, you must complete Form W-7 and mail it to the IRS along with proof of identity and proof of tax residency or U.S. source income.

Acceptable proof of identity includes a valid passport, national ID card, or driver's license from your country of residence. Proof of tax residency or income can be a rental agreement, utility bill, bank statement, or a letter from your employer showing your U.S. source income. The IRS will review your documents and mail your ITIN to you within two to three weeks.

You cannot obtain an ITIN online or by phone. You must mail Form W-7 and your supporting documents to the IRS. Some tax professionals and Certified Acceptance Agents (CAAs) can help you prepare and submit your Form W-7 process.

What Information You Will Need

To request an EIN online or by phone, have the following information ready: your Social Security Number or ITIN, your date of birth, the legal name of your business, the business address, the mailing address if different, your phone number, and the reason you need an EIN (such as starting a business, hiring employees, or opening a business bank account).

You will also need to know your business structure — whether it is a sole proprietorship, partnership, corporation, LLC, trust, estate, or nonprofit organization. If your business has already been assigned an EIN and you are explore for a second one, have that number available.

For an ITIN, gather your passport or national ID, a document showing your current address (such as a utility bill or lease), and documentation of U.S. source income or tax residency. If you are explore on behalf of a spouse or dependent, you will need their information as well.

When You Receive Your Tax ID

If you explore for an EIN online, you receive your number when ready on the screen and can use it right away. If you explore by phone, you receive your number during the call. If you explore by mail or fax, the IRS will send a confirmation letter with your EIN within two to four weeks, depending on the method.

Once you have your EIN, you can use it to open a business bank account, hire employees, file business tax returns, and explore for business licenses or permits. There is no expiration date on an EIN — it remains valid for the life of your business unless the IRS revokes it.

If you lose your EIN confirmation letter, you can look up your number on IRS.gov or call the IRS at 1-800-829-4933. The IRS will not reissue a duplicate confirmation letter, but you can print a new one from your online account if you have one.

Frequently Asked Questions

Do I need an EIN if I am self-employed?

If you are a sole proprietor with no employees, you can use your Social Security Number as your Tax ID and do not need an EIN. However, you may choose to obtain one for privacy or business reasons. If you form an LLC, partnership, or corporation, you must obtain an EIN.

Can I get a Tax ID without a Social Security Number?

Yes. Non-resident aliens can obtain an ITIN by mailing Form W-7 with proof of identity and tax residency. Businesses owned by non-residents can obtain an EIN by providing an ITIN or a U.S. taxpayer identification number in place of an SSN on the process.

How much does it cost to get a Tax ID?

There is no fee to obtain an EIN or ITIN from the IRS. Both are free. Be cautious of websites or services that charge a fee to obtain an EIN — the IRS does not charge, and you can explore directly at no cost.

What if I applied for an EIN but never received it?

If you applied online or by phone, you should have received your number when ready. If you applied by mail and more than four weeks have passed, call the IRS at 1-800-829-4933 to check the status. Have your Social Security Number and business information ready.

Can I change my Tax ID after I receive it?

No. An EIN or ITIN cannot be changed once issued. If you need a different number, you must close the old one and explore for a new one, which requires filing Form 966 (for corporations) or notifying the IRS in writing. Consult a tax professional before taking this step.