Do All Businesses Need an EIN? Rules, Exceptions, and How to Apply

Not all businesses need an EIN, but most do. Corporations, partnerships, multi-member LLCs, and nonprofits are required to have an Employer Identification Number from the moment they’re formed. Sole proprietors and single-member LLCs can usually get by with a Social Security Number, until they hire an employee or take on one of a handful of specific tax obligations that force the issue.

Businesses That Must Have One

Federal regulations require any non-individual entity that has to furnish a taxpayer identification number to use an EIN rather than an owner’s Social Security Number.1eCFR. 26 CFR 301.6109-1 – Identifying Numbers That rule reaches four categories of business:

  • Corporations, both C corps and S corps, which are legally separate from their shareholders.
  • Partnerships of every kind: general, limited, and limited liability.
  • Multi-member LLCs, which the IRS treats as partnerships by default.
  • Nonprofit organizations, even ones that will never have employees.2Internal Revenue Service. Employer Identification Number

For these entities, the business and its owners are separate taxpayers in the eyes of the IRS. Filing information returns with a missing or incorrect identification number triggers penalties under IRC Section 6721. For returns due in 2026, those penalties start at $60 per return if corrected within 30 days, climb to $130 if corrected by August 1, and reach $340 per return after that.3Internal Revenue Service. 20.1.7 Information Return Penalties

When a Sole Proprietor Is Forced to Get One

A sole proprietor who normally files under a Social Security Number can hit a trigger that makes an EIN mandatory. The most common: hiring a single employee. Once you have someone on payroll, you need an EIN to report employment taxes and federal unemployment obligations.4Internal Revenue Service. Employer Identification Number

Other activities that flip the switch:

  • Operating a Keogh retirement plan, which requires its own EIN for annual reporting on Form 5500-EZ.
  • Filing excise, alcohol, tobacco, or firearms tax returns, which demand an EIN regardless of business structure.5Internal Revenue Service. Get an Employer Identification Number
  • Administering a trust or estate. Executors must apply for an EIN when an estate needs to file its own income tax return.6Internal Revenue Service. Information for Executors

Skipping the EIN when one of these triggers applies isn’t just a paperwork miss. Back taxes, interest on unpaid payroll liabilities, and the information-return penalties above can stack quickly.

When Your Social Security Number Is Enough

If you’re a sole proprietor with no employees and none of the triggers above apply, you can use your SSN on federal tax filings. Business income goes on Schedule C under your personal identification number, and the IRS won’t require a separate EIN.7Internal Revenue Service. Instructions for Schedule C (Form 1040)

Single-member LLCs get the same treatment as long as they haven’t elected to be taxed as a corporation. The IRS calls these “disregarded entities,” meaning the owner and the business are the same taxpayer for federal income tax purposes. A single-member LLC that files employment, excise, or firearms returns still needs an EIN for those specific filings, but the owner’s SSN covers the income tax side.7Internal Revenue Service. Instructions for Schedule C (Form 1040)

Why You Might Want One Anyway

Plenty of sole proprietors and single-member LLC owners get an EIN voluntarily. The reasoning is straightforward: your SSN otherwise ends up on every W-9 you hand a client, every 1099 they file, and every business credit application you submit. That’s a lot of exposure. An EIN keeps your Social Security Number off most business paperwork and reduces identity theft risk.

Banking is easier with one, too. A sole proprietor can technically open a business account using an SSN, but an EIN separates business finances cleanly and avoids confusion if you later add employees or change your structure. The application is free and takes minutes.

How to Get One if You Need It

The IRS does not charge a fee for an EIN, regardless of how you apply.5Internal Revenue Service. Get an Employer Identification Number The fastest route is the IRS EIN Assistant online, which issues the number immediately upon validation. To use it, the responsible party must have a valid SSN or ITIN, and the business must have a principal place of business or legal residence in the United States or its territories.8Internal Revenue Service. Instructions for Form SS-4

If you’d rather use paper, complete Form SS-4 and fax it in with a return fax number; you’ll typically get the EIN within four business days. Mailing the form works too, but plan on four to five weeks. Applicants with no legal residence, business address, or office in the United States can’t use the online tool, but they can call 267-941-1099 (not toll-free), Monday through Friday, 6:00 a.m. to 11:00 p.m. Eastern, and an IRS representative will walk through the Form SS-4 questions and assign the EIN during the call.8Internal Revenue Service. Instructions for Form SS-4

Have the following ready before you start:

  • The legal name of the entity, matching exactly what appears on the charter, articles of organization, or Social Security card for sole proprietors.
  • A physical street address. A P.O. box won’t do.
  • The responsible party: one individual who controls or manages the entity, providing their own SSN or ITIN.8Internal Revenue Service. Instructions for Form SS-4
  • A reason for applying, such as starting a new business, hiring employees, or opening a bank account.

If the responsible party later changes, you have 60 days to notify the IRS by filing Form 8822-B.9Internal Revenue Service. Form 8822-B Change of Address or Responsible Party – Business

Avoid Paid EIN Websites

A cottage industry of websites mimics the IRS EIN Assistant and charges up to $300 for something the IRS provides for free. Some use terms like “IRS” or “EIN Assistant” in their branding to suggest a government connection.10Federal Trade Commission. FTC Warns Operators of Websites that Charge for an Employer Identification Number The only legitimate free source is irs.gov. If a site asks for payment to file your EIN application, close the tab.