IRS

Form SS-4

Rev. 12/2023

Application for Employer Identification Number (EIN)

Used to apply for a Federal Employer Identification Number (EIN).

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Plain English

Form SS-4 is used to apply for an Employer Identification Number (EIN) — the business equivalent of a Social Security Number. You need an EIN if you start a business, hire employees, or operate as a corporation or partnership.

Quick Facts

Who: Business owners who need an EIN — corporations, partnerships, LLCs, trusts, estates, sole proprietors with employees, or anyone required to file employment/excise tax returns.
What: Application for a Federal Employer Identification Number (EIN) — a unique 9-digit number used to identify a business entity for tax purposes.
When: Before you need to file business tax returns, hire employees, open a business bank account, or establish business credit.
Where: Apply online through IRS website (instant). Alternatively, fax or mail SS-4 to IRS.
Why: An EIN is required to pay employees, file business tax returns (941, 940, etc.), open business bank accounts, and establish business credit.
How: Enter legal entity name, DBA (if any), responsible party info, entity type, reason for applying, business start date, principal activity, and expected number of employees.

Common Risks & Mistakes

  • •Applying for multiple EINs for the same entity — one EIN per legal entity; banks/IRS may flag duplicates
  • •Wrong responsible party — the person who owns or controls the entity must be listed with their SSN/ITIN
  • •Incorrect entity type — selecting wrong structure (sole prop vs. partnership vs. corp) affects reporting requirements
  • •Not applying when required — operating without an EIN when required can cause penalties
  • •Confusing EIN application with state business registration — EIN is federal; separate state registration may be needed

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Field-by-Field Guide

Entity
Legal Name of EntityREQUIREDtext

The legal name exactly as filed with the state or as it appears on legal documents.

Trade Name (DBA)text

Doing business as name, if different from legal name.

Responsible Party Name & SSN/ITINREQUIREDtext

The individual who controls, manages, or directs the entity. Must provide their SSN or ITIN.

Mailing AddressREQUIREDtext

Where IRS correspondence will be sent.

Type of EntityREQUIREDselect

Sole proprietor, partnership, corporation, S-corp, LLC, trust, estate, etc.

Reason
Reason for ApplyingREQUIREDtext

Started a new business, hired employees, banking purposes, changed type of organization, etc.

Business
Date Business StartedREQUIREDdate

Date the entity was formed or started operating.

Principal Business ActivityREQUIREDtext

Describe the primary type of product or service.

e.g. Retail sale of clothing
Number of Employees Expected in Next 12 Monthstext

If hiring, provide expected headcount to determine filing requirements.

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Form Stats

9
Fields
7
Required
3
Sections

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Disclaimer: We do not provide legal advice. We translate legal language into plain English and help you prepare for a conversation with a lawyer.