EIN Application (Form SS-4): Complete 2026 Guide for US and Foreign Founders

What an EIN Actually Is

An Employer Identification Number (EIN) is a nine-digit federal tax identification number issued by the IRS in the format XX-XXXXXXX. Every US entity that hires employees, files federal tax returns, opens a bank account, or operates as anything other than a sole proprietor needs an EIN. The EIN is the entity-level equivalent of a Social Security Number, it identifies the entity to the IRS, to banks, to state tax authorities, and to payroll processors.

EINs are issued by the IRS for free. There is no government filing fee. Third-party services that charge to "obtain an EIN" are charging only for the convenience of doing the application on your behalf, the IRS itself never charges for the number.

EINs are permanent. Once issued, an EIN stays with the entity for life. Closing the entity does not retire the EIN, the IRS keeps the number in its records and will not reissue it. If you start a new entity, you get a new EIN.

Who Needs an EIN

At a Glance

Item	Value
Form	IRS Form SS-4
Cost	$0 (free) for the IRS application
Online processing	Same-day (for US-based applicants with SSN/ITIN)
Fax processing	4 business days
International (no SSN/ITIN)	Phone application or fax: 4 weeks

Every LLC, corporation, partnership, and nonprofit needs an EIN, even if it has no employees and no revenue. The EIN is required to open a business bank account, file federal tax returns, hire employees, register for payroll, apply for business licenses, and submit information returns (1099s).

Single-member LLCs without employees can technically use the owner's Social Security Number for federal tax purposes, but every bank requires an EIN to open a business account, so SMLLCs always end up needing one.

Sole proprietors do not need an EIN unless they have employees. They can use their SSN. But many sole proprietors get an EIN anyway to avoid using their SSN on 1099s and W-9s issued to clients.

Foreign-owned LLCs (including foreign-owned SMLLCs) need an EIN, regardless of whether they have US source income. This is essential for Form 5472 reporting (covered separately in this series).

How to Apply for an EIN

The IRS offers three application paths, each with different speed and eligibility requirements.

Path 1: Online Application (Fastest, Same Day)

The IRS online EIN Assistant issues an EIN immediately upon completion. The application takes about 15 minutes. The EIN is delivered as a PDF confirmation letter (CP 575) at the end of the session, save it immediately, the IRS does not email a copy.

Eligibility: the "responsible party" (the person controlling the entity) must have a valid SSN, ITIN, or existing EIN. Foreign founders without any of these CANNOT use the online application.

Hours: the IRS online EIN Assistant operates Monday through Friday, 7am to 10pm Eastern Time. It does not operate on weekends or federal holidays. The single-session timeout is 15 minutes, you must complete the application without breaks.

Restriction: only one EIN per responsible party per day via the online system. If you are forming multiple entities for different clients or family members in the same day, you must use fax or phone for the additional applications.

Path 2: Fax Application (4 Business Days)

For applicants who cannot use the online system (no SSN/ITIN, or already at the daily limit), the fax path is the next-fastest option. Fax the completed SS-4 to the IRS at +1-855-641-6935 (US applicants) or +1-855-215-1627 (international applicants without a US legal residence).

Processing time: 4 business days. The IRS faxes the EIN back to the number provided on the SS-4. If no fax number is provided, the EIN is mailed (adds 4-5 weeks).

Documentation: the responsible party must be a US citizen, US resident alien, or have an ITIN. Foreign founders without SSN/ITIN can still use fax, they enter "Foreign" in the responsible party SSN/ITIN field.

Path 3: International Phone Application

For foreign founders without SSN, ITIN, or US legal residence: call the IRS International Tax Service at +1-267-941-1099 (NOT a toll-free number; international rates apply). The line operates Monday through Friday, 6am to 11pm Eastern Time.

Have the completed SS-4 in front of you when you call. The IRS agent walks through the form line-by-line and issues the EIN at the end of the call. Total call time is typically 30-45 minutes.

Documentation: passport number, foreign address, and the entity's US formation state and date. The responsible party can be a foreign individual living abroad.

Processing time: immediate on the phone call. The EIN confirmation letter (CP 575) is mailed within 4 weeks to the foreign address.

The "Responsible Party" Requirement

The IRS requires every EIN application to identify a "responsible party", the individual who controls, manages, or directs the entity and the disposition of its funds and assets. This is typically an owner with the most decision-making authority.

The responsible party must be an individual, not another entity. A parent corporation cannot be the responsible party for its subsidiary, a specific human must be named.

The responsible party can be updated later via Form 8822-B (covered in the IRS records-update section of this guide). The EIN itself stays the same, only the responsible-party name and address change.

For foreign-owned LLCs: the responsible party can be a foreign individual without an SSN. The fax and phone application paths accommodate this.

Common EIN Application Mistakes

Mistake 1: Applying for an EIN before the LLC or corporation is approved by the state. The IRS requires the entity to exist before issuing an EIN. Wait for the formation document to be approved.

Mistake 2: Using a third-party service that charges $100-$300 for a free IRS application. Unless you specifically need help with foreign-founder application paths, do it yourself for free.

Mistake 3: Naming an entity (not a person) as the responsible party. The IRS rejects these applications. The responsible party must always be an individual.

Mistake 4: Losing the CP 575 confirmation letter. The IRS only issues CP 575 once. If lost, request a 147-C letter (EIN verification), it takes several weeks and you cannot get the original CP 575 back.

Mistake 5: Not understanding the single-EIN-per-day online limit. Multiple-entity formation clients (attorneys, accountants, formation services) hit this constantly. Plan around it.

What to Do After Getting Your EIN

Open a business bank account immediately. Banks require the EIN confirmation letter (CP 575). Without it, you cannot deposit revenue under the entity name.

Register for state employer accounts if you will hire employees. Each state requires a separate state employer account (state unemployment insurance + state withholding).

File Form 2553 if electing S-corporation tax treatment (covered separately in this series).

File Form 8832 if electing C-corporation or partnership treatment for an entity that would otherwise be taxed differently (covered separately in this series).

Update your state of formation if you elected a different tax classification, most states automatically follow federal classification, but check.

How File.Business Handles EIN Applications

File.Business handles EIN applications as part of every LLC and corporation formation. For US founders with SSN/ITIN, we use the online IRS EIN Assistant for same-day issuance. For foreign founders, we handle the IRS International Tax Service phone call or fax application, including preparing the SS-4, coordinating the responsible-party documentation, and delivering the CP 575 confirmation letter to your document vault.

Standalone EIN service: $99 flat for foreign founders without SSN/ITIN (where the IRS phone or fax path is required). For US founders, the online EIN application is free and we recommend doing it yourself, the application takes 15 minutes and there is no benefit to paying a third party.

Frequently Asked Questions

How much does an EIN cost?

The IRS does not charge for an EIN, applications are free. Third-party services charge a convenience fee for handling the application. Foreign founders without SSN/ITIN typically pay $99-$300 because the phone or fax path requires US-based handling.

How fast can I get an EIN?

Same-day if you use the IRS online EIN Assistant (US applicants with SSN/ITIN). 4 business days via fax. Immediate via the IRS International Tax Service phone call (foreign founders). The CP 575 confirmation letter is mailed within 4 weeks.

Can a foreign founder get an EIN without an SSN or ITIN?

Yes. Foreign founders apply via fax or by calling the IRS International Tax Service at +1-267-941-1099. The phone application issues the EIN during the call. The responsible party can be a foreign individual living abroad, no US presence required.

Do I need a US address to get an EIN?

No. The IRS accepts foreign addresses for the responsible party. The entity itself must be formed in a US state (which requires a US registered agent address), but the responsible party can be located abroad.

What is the "responsible party" on Form SS-4?

The individual who controls, manages, or directs the entity and the disposition of its funds and assets. Must be a person (not an entity). Can be updated later via Form 8822-B without changing the EIN.

What if I lose my EIN confirmation letter (CP 575)?

Request a 147-C letter from the IRS (EIN verification). Call the IRS Business and Specialty Tax Line at +1-800-829-4933. The 147-C letter is mailed within 4-5 weeks. Banks and the IRS accept 147-C as equivalent to CP 575.

Can my LLC change its EIN if I add members?

No. EINs are permanent for the entity. Changing from single-member to multi-member changes the federal tax classification (disregarded entity to partnership) but the EIN stays the same.