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Key Facts
- Federal level: An EIN is a federal tax identification number issued by the IRS to businesses and other entities for filing and reporting.
- Federal level: The IRS issues EINs without a fee; websites charging for applications are third-party services, not the IRS.
- Federal level: Domestic applicants can apply online, by fax, or by mail; telephone applications are limited to international applicants.
- Federal level: The entity should generally be legally formed before applying and must identify its true responsible party, not a nominee.
- Federal level: EIN issuance is limited to one per responsible party per day across all application methods.
- Federal level: An EIN does not create an entity, select its federal tax classification, provide a license, or grant tax-exempt status.
How to get an EIN
An employer identification number, or EIN, is a nine-digit federal taxpayer identification number assigned by the Internal Revenue Service. Businesses, tax-exempt organizations, estates, trusts, retirement plans, and other entities use it on federal returns and information documents.
The IRS application is free. A domestic applicant can usually obtain an EIN through the IRS online application, or submit Form SS-4 by fax or mail. An applicant without a legal residence, principal place of business, or principal office or agency in the United States or its territories cannot use the online application and may use the international telephone process, fax, or mail.
Confirm that an EIN is needed
An entity commonly needs an EIN if it has employees, operates as a corporation or partnership, administers certain retirement plans, files specified employment or excise returns, or fits another category listed on Form SS-4. Estates, many trusts, and tax-exempt organizations also use EINs.
A sole proprietor without employees or applicable filing duties may sometimes use the owner’s Social Security number for federal tax purposes. Practical requirements from a bank, payroll provider, or state agency can still make an EIN useful. The IRS eligibility questions should be applied to the actual entity.
Obtaining an EIN is not the same as forming a limited liability company or corporation. Formation occurs under state or tribal law. An EIN also does not choose how an LLC is federally classified, replace a state tax account, establish payroll compliance, or approve exemption under section 501(c).
Form the entity before applying
The IRS advises applicants to complete legal formation before requesting an EIN. This allows the application to use the entity’s exact legal name and formation date. For exempt organizations, applying too early can also start the federal filing clock before the organization is operational.
Gather the formation document, legal name, trade name if any, mailing and physical addresses, entity type, formation state and date, closing month of the accounting year, expected employee count, first wage date, and principal activity. Inconsistent legal names or classifications can delay later return processing.
Identify the responsible party
Form SS-4 requires a responsible party: the person who ultimately owns or controls the entity or exercises ultimate effective control over it and its funds. Except for government entities, the responsible party must generally be an individual rather than another entity.
For a corporation, this is usually the principal officer; for a partnership, a general partner; for a trust, the grantor, owner, or trustor; and for an estate, the executor or other fiduciary. A nominee with only limited formation authority cannot apply or be listed as the responsible party.
The responsible party generally supplies an SSN or ITIN. The online application also requires the principal officer, partner, grantor, owner, or trustor to have a valid taxpayer identification number. Form 8822-B is used to report a later responsible-party change, generally within 60 days.
Apply online when eligible
The IRS recommends electronic application when possible. Online eligibility requires a legal residence, principal business, or principal office or agency in the United States or a U.S. territory. The application must be completed in one session, and the responsible party’s taxpayer identification information must be available.
After successful submission, the IRS assigns the EIN and offers an assignment notice that can be viewed, printed, and saved. Preserve that notice securely because banks, tax agencies, payroll providers, and future IRS contacts may request verification.
The IRS limits issuance to one EIN per responsible party per day, including requests submitted online, by fax, mail, or international telephone. Submitting duplicate applications through multiple channels can create conflicting accounts and should be avoided.
Apply by fax or mail
Applicants can complete, sign, and submit Form SS-4 using the current address or fax number in the instructions. The December 2025 instructions state that a fax response is generally available within four business days when a return fax number is provided. A mailed application should be submitted at least four to five weeks before the number is needed.
Addresses and fax numbers can change, so the current Form SS-4 instructions and IRS filing-location page should be checked immediately before submission. Only one method should be used for the same entity.
International applicants
An applicant with no legal residence, principal place of business, or principal office or agency in the United States or its territories cannot use the online EIN application. The current instructions allow such an applicant to call the IRS international EIN line during published hours or apply by fax or mail.
The caller must be authorized to receive the EIN and answer Form SS-4 questions. Completing the form in advance makes the telephone interview more reliable. Domestic applicants cannot obtain an EIN by telephone.
Third-party designees
A properly authorized third-party designee can receive the newly assigned EIN and answer questions about Form SS-4. The applicant must complete the designation and signature areas. This limited authority ends when the EIN is assigned and released to the designee.
A designee is not necessarily the responsible party. The application must still identify the individual who actually controls the entity. Paid filing services do not receive special IRS priority and should not be confused with the free government application.
Choose the entity answer carefully
Form SS-4 asks for the entity type and reason for applying. A domestic single-member LLC is generally disregarded for federal income tax unless it elects corporate treatment, while a multi-member domestic LLC generally defaults to partnership treatment unless it elects otherwise. The EIN application does not itself make every tax election.
A business changing from a sole proprietorship to a corporation or partnership may need a new EIN because ownership or structure changed. A mere business-name, address, or responsible-party change generally does not require a new EIN. An owner buying corporate stock generally does not use the corporation’s ownership change as a reason to replace its EIN.
The related overview of how an LLC files federal taxes explains why legal form and federal tax classification must remain separate.
After the EIN is issued
Use the legal name and EIN consistently on federal returns, payroll filings, payment accounts, and information returns. Store the assignment notice with permanent entity records. If the number is lost, check the notice, prior returns, bank records, and licensing applications before contacting the IRS business line.
An EIN cannot be canceled, but the IRS can deactivate an account that is no longer needed after required returns and taxes are addressed. Do not obtain a replacement merely because the original number was forgotten.
Finally, complete any separate state registrations, payroll accounts, licenses, beneficial-ownership reporting, and tax elections that apply. The EIN is an essential federal identifier, not a complete business-registration package.
