Taxes & Business

EIN (Employer Identification Number)

Also known asEmployer Identification NumberFederal Tax IDFEIN

Definition

An Employer Identification Number (EIN) is a nine-digit federal tax ID issued by the IRS to identify business entities, trusts, and estates for tax filings, banking, and payroll. Most entities other than single-member LLCs without employees need an EIN; obtaining one is free directly from the IRS.

By Olomon EditorialLast updated
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Key takeaways

  • EINs are issued by the IRS — not by states.
  • An EIN is required to file business tax returns, hire employees, and open most business bank accounts.
  • Trusts and estates frequently need their own EINs for tax filings.
  • Apply directly at IRS.gov — third-party services charge for what is a free service.

How Olomon thinks about this

Olomon treats each entity as a record with its own EIN, formation documents, ownership, governance, and balance sheet. That collapses the typical “which LLC owns what?” guessing game into a single source of truth.

Quick facts

  • FormatNine digits, NN-NNNNNNN
  • Issuing authorityInternal Revenue Service[1]
  • Cost to obtainFree directly from IRS.gov[1]
  • Application formIRS Form SS-4 (or online application)[1]
  • Online turnaroundIssued immediately on completion[1]

In-depth definition

EINs are the social security numbers of legal entities. They appear on tax filings, payroll records, bank account openings, and credit applications. Households who run multiple LLCs, trusts, or other entities should keep an inventory of every EIN they own — it is a small data point that becomes critical at tax time, in due diligence, and during estate administration.

How to get an EIN

The procedural steps to obtain an Employer Identification Number directly from the IRS, free of charge.

  1. 1

    Confirm you need an EIN

    An EIN is required if you have employees, operate as a corporation or partnership, file employment / excise / alcohol-tobacco-firearms tax returns, withhold taxes on income paid to non-resident aliens, or operate certain trusts and estates.

  2. 2

    Identify the responsible party

    Designate a responsible party — the individual who controls, manages, or directs the entity and the disposition of its funds. The responsible party must have a valid SSN, ITIN, or EIN.

  3. 3

    Apply directly through IRS.gov

    Use the IRS EIN online application during operating hours (M–F, 7am–7pm Eastern). The application is free and the EIN is issued immediately upon successful completion. International applicants apply by phone; paper Form SS-4 by fax or mail is also accepted.

  4. 4

    Save the CP 575 confirmation notice

    Download and securely store the EIN assignment confirmation (Notice CP 575). Banks, payroll providers, and tax preparers will request it.

  5. 5

    Use the EIN for federal filings

    Use the EIN on every federal tax filing, payroll filing, employer information return, and (typically) bank account opening for the entity going forward.

Frequently asked questions

  • No. The EIN is federal. Many states issue separate IDs for state income tax, sales tax, or employer registration purposes.

Sources

Primary, authoritative references.

  1. 1

    Internal Revenue Service (IRS)

    Apply for an Employer Identification Number (EIN) Online

    Cited for: Authoritative IRS application path

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Cite this page

APA
Olomon Editorial Team. (2026). EIN (Employer Identification Number). Olomon Financial Glossary. https://olomon.com/financial-glossary/ein-employer-identification-number

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