Form SS-4 & EIN Application

What Is an EIN? Why You Need Form SS-4 to Get Your Tax ID Number

4 min readQ&A Guide

Written byLipai WangFounder · IRS-registered tax professional

Filing path

EIN application flow (Form SS-4)

How a foreign-owned entity obtains its IRS Employer Identification Number.

Gather entity details
Legal name, responsible party, and structure.
Complete Form SS-4
Foreign responsible parties can generally apply without a U.S. TIN when the IRS foreign-applicant process applies.
Submit to the IRS
Fax or mail — international applicants can also call.
Receive the EIN
Use it to open banking and file federal returns.

Key formsForm SS-4EIN

Key Takeaways

An EIN is a 9-digit federal tax ID number assigned to business entities by the IRS
Form SS-4 is the official IRS application used to obtain an EIN
The IRS limits EIN issuance to one per responsible party per business day
Your EIN goes on all business tax returns, employment filings, and bank account applications
Apply for your EIN after entity formation but before your first filing deadline
Keep SS-4 information consistent with your legal formation documents
Use Form 8822-B to report changes to the IRS within 60 days

What exactly is an EIN, and how is it different from an SSN or ITIN?

An Employer Identification Number (EIN) is a 9-digit number the IRS assigns to business entities for tax filing and reporting purposes. Think of it as a Social Security Number for your business. The format is XX-XXXXXXX (two digits, a hyphen, then seven digits).

Unlike an SSN (which is for U.S. citizens and permanent residents) or an ITIN (which is for individuals who need to file taxes but are not eligible for an SSN), an EIN is specifically for entities: LLCs, corporations, partnerships, trusts, estates, and certain sole proprietorships. You use the EIN on all business tax returns, employment filings, and when opening business bank accounts.

Why does the IRS require you to get an EIN?

The IRS uses EINs to track business tax obligations. Every entity that files its own tax return, withholds taxes, or has employees needs its own unique identifier. Without an EIN, the IRS has no way to match your business filings to the correct entity.

For foreign-owned U.S. LLCs, the EIN is essential because it goes on your annual Form 5472 and pro forma Form 1120. Banks also require an EIN to open a business checking account, and payment processors like Stripe need it to set up merchant services.

What is Form SS-4 and how does it relate to getting an EIN?

Form SS-4 (Application for Employer Identification Number) is the official IRS form you use to apply for an EIN. It collects information about your entity: the legal name, address, entity type, responsible party, and the reason you need the number.

Think of Form SS-4 as the setup document for your IRS business tax account. Every piece of information you put on SS-4 becomes part of your IRS master file. That is why accuracy matters so much. The name, address, and entity type on your SS-4 need to match your legal formation documents exactly.

Can the IRS limit how many EINs you get?

Yes. The IRS limits EIN issuance to one per responsible party per day. This means if you are listed as the responsible party on multiple entities, you can only obtain one EIN per business day. If you need EINs for several new entities, plan to apply on separate days.

This limitation applies across all application methods (online, phone, fax, and mail). It was put in place to prevent abuse and ensure proper processing.

When should you apply for an EIN?

Apply for your EIN after your entity is legally formed but before you need to file any tax returns, open bank accounts, or hire employees. The best practice is to apply as soon as your Articles of Organization or Certificate of Incorporation are filed and approved by the state.

Do not wait until your first tax return is due. Processing times vary by method (instant online, a few days by fax, or several weeks by mail), so give yourself a buffer. If you need the EIN before your entity is fully set up, you can write "Applied For" on forms that require it.

Frequently Asked Questions

Is an EIN the same as a tax ID number?

Yes, in the business context. EIN stands for Employer Identification Number and is also called a Federal Tax Identification Number. It serves the same purpose for businesses that an SSN serves for individuals.

Do I need a new EIN if I change my LLC's name?

Generally no. A name change alone does not require a new EIN. Instead, you report the change to the IRS using Form 8822-B (Change of Address or Responsible Party) and notify the IRS in writing.

Can I apply for an EIN before my LLC is formed?

No. You should wait until your entity is legally formed (Articles of Organization filed and approved) before applying for an EIN. The IRS needs your entity to exist legally before assigning a number.

Does getting an EIN cost anything?

No. The IRS does not charge any fee for issuing an EIN. Beware of third-party websites that charge fees to file Form SS-4 on your behalf. You can apply directly through the IRS at no cost.

form ss-4EINemployer identification numbertax IDEIN application

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