An EIN and a federal tax ID are not quite the same thing, though the terms are often used interchangeably

A federal tax ID is an umbrella term for any identification number the IRS uses to track a taxpayer. An EIN — Employer Identification Number — is one specific type of federal tax ID. Think of it this way: all EINs are federal tax IDs, but not all federal tax IDs are EINs. The IRS issues different numbers depending on what kind of entity you are and what you do.

If you are a sole proprietor with no employees, you typically use your Social Security Number as your federal tax ID. If you run a business with employees, or if you operate as a partnership, corporation, or LLC, you need an EIN. The EIN is a nine-digit number formatted as XX-XXXXXXX. It is the federal tax ID that the IRS assigns to your business entity itself, separate from any individual's personal tax number.

The confusion arises because many people use "federal tax ID" and "EIN" to mean the same thing in conversation, and in many business contexts, they function the same way — both identify you to the IRS for tax purposes. But technically, they are different categories, and knowing the difference matters when you are filling out forms or talking to a bank or accountant about which number you actually need.

Key Takeaways

  • A federal tax ID is any number the IRS uses to identify a taxpayer; an EIN is one specific type of federal tax ID issued to businesses and other entities.
  • Sole proprietors without employees typically use their Social Security Number as their federal tax ID, not an EIN.
  • Businesses with employees, partnerships, corporations, and LLCs must obtain an EIN, which is a nine-digit number the IRS assigns to the business entity itself.
  • An EIN is required to open a business bank account, hire employees, and file certain tax forms, even if you have no income yet.

Types of Federal Tax IDs the IRS Issues

The IRS uses several different federal tax ID numbers depending on who or what is being identified. Your Social Security Number (SSN) is a federal tax ID if you are a sole proprietor filing Schedule C on your personal 1040 form. A Taxpayer Identification Number (ITIN) is a federal tax ID issued to non-citizens who need to file taxes but do not have an SSN. An Employer Identification Number (EIN) is issued to businesses, partnerships, corporations, LLCs, nonprofits, and trusts.

There is also the PTIN — Preparer Tax Identification Number — which is a federal tax ID for tax professionals who prepare returns for others. And the ATIN — Adoption Taxpayer Identification Number — is a temporary federal tax ID used in adoption cases. Each serves a different purpose and is issued under different circumstances. When someone asks for your "federal tax ID," they usually mean whichever of these numbers applies to your situation.

When You Need an EIN Instead of Just an SSN

You need an EIN if you operate any business structure other than a sole proprietorship, or if you operate a sole proprietorship but have employees. The IRS requires an EIN for partnerships, S corporations, C corporations, LLCs, nonprofits, trusts, and estates. You also need an EIN if you are a sole proprietor and you have hired even one employee, because the EIN is what you use to report payroll taxes and file employment tax forms like the 941 (quarterly payroll tax return).

Some sole proprietors obtain an EIN even when they are not required to, because they want to keep their business finances separate from their personal finances, or because they plan to hire employees in the future. Banks often prefer to see an EIN when opening a business account, even though technically a sole proprietor can use an SSN. If you are unsure whether you need one, the safest approach is to obtain an EIN — it is free and takes about 15 minutes to request online through the IRS website.

How an EIN Differs From an SSN in Tax Reporting

When you file taxes as a sole proprietor using only your SSN, you report business income and expenses on Schedule C, which attaches to your personal 1040 form. Your business and personal finances are legally one entity. When you have an EIN, your business is a separate entity for tax purposes (even if you are the sole owner of an LLC). You file a separate business tax return — such as Form 1120 for a corporation or Form 1065 for a partnership — in addition to your personal 1040.

An EIN also means the IRS can track employment taxes separately. If you have employees, you use the EIN to file Form 941 (Employer's Quarterly Federal Tax Return) and to report W-2 wages. You cannot do this with an SSN. Additionally, an EIN is what you provide to banks, vendors, and contractors for 1099 reporting purposes. An SSN, by contrast, is personal to you and should not be shared for business purposes beyond what is legally required.

How to Obtain an EIN

You can obtain an EIN for free through the IRS website at irs.gov. The online process (Form SS-4) takes about 15 minutes and you receive your EIN when ready upon completion. You do not need to mail anything or wait for a letter. You will need your business name, business address, the type of business structure, and your SSN or ITIN.

If you prefer not to explore online, you can mail Form SS-4 to the IRS, though this takes several weeks. You can also call the IRS Business and Specialty Tax Line at 1-800-829-4933, but phone applications are slower than the online method. Once you have an EIN, it does not expire and you do not renew it. The IRS will send you a confirmation letter, which you should keep for your records.

EIN vs. Federal Tax ID on Forms and Applications

When a form asks for your "federal tax ID," you should enter whichever number applies to you: your SSN if you are a sole proprietor without employees, or your EIN if you have one. Some forms specifically ask for an "EIN" and will not accept an SSN — this is common on business bank account applications and contractor agreements. Other forms ask for "Tax ID" and will accept either, depending on your business structure.

The key is to read the form carefully. If it says "EIN required," you must have one. If it says "Tax ID" or "Federal Tax ID," you can use your SSN if you do not have an EIN, but if you do have an EIN, you should use that instead. Providing the wrong number can delay processing or cause the form to be rejected. When in doubt, contact the organization requesting the number and ask which one they need.

Frequently Asked Questions

Can I use my SSN instead of an EIN for my business?

Only if you are a sole proprietor with no employees. If you have any employees, operate as a partnership, corporation, LLC, or nonprofit, you must have an EIN. Many sole proprietors obtain an EIN anyway to keep business and personal finances separate and to prepare for future hiring.

Do I need an EIN if I have not started making money yet?

No, but you may want one. If you are opening a business bank account or hiring employees before your first sale, you will need an EIN. If you are just planning a business and have not taken any concrete steps, you can wait until you actually need it.

Is an EIN the same as a business license?

No. An EIN is a federal tax identification number issued by the IRS. A business license is a permit issued by your state or local government that allows you to operate legally in that jurisdiction. You may need both, but they serve different purposes and are obtained from different agencies.

What if I lose my EIN number or forget it?

You can look it up on the IRS website using your business name and SSN, or call the IRS Business and Specialty Tax Line. The IRS also sent you a confirmation letter when you received the EIN — check your records. Your EIN never changes, so once you have it, you keep it for the life of the business.

Can I have more than one EIN?

Yes, if you operate multiple separate business entities. Each business structure — each LLC, corporation, or partnership — gets its own EIN. However, if you own multiple businesses under the same legal entity, you have only one EIN for all of them.