SS-4 form (EIN)
Fill in IRS Form SS-4 online to apply for an Employer Identification Number (EIN), then download it to fax or mail.
Form SS-4, Application for Employer Identification Number, is how a business, trust, estate or other entity asks the IRS for an EIN. The official form (Rev. December 2025) opens here ready to type into. Fill it in, download it, sign it and fax or mail it to the IRS. An EIN is free: the IRS never charges for one.
How to fill out Form SS-4
- The official blank Form SS-4 opens automatically.
- Fill in the entity’s name and address, the responsible party, the type of entity and the reason for applying.
- Download the PDF, sign it with Sign PDF, and fax or mail it to the IRS.
Frequently asked questions
What is Form SS-4 used for?
Form SS-4 is the application for an Employer Identification Number (EIN), the nine-digit number the IRS uses to identify a business, trust, estate, nonprofit or other entity. You need an EIN to hire employees, open most business bank accounts and file business tax returns.
How much does an EIN cost?
Nothing. The IRS issues EINs free of charge. Websites that charge a fee are private filing services, not the IRS.
Is it faster to apply online?
Yes. If the business is in the United States and the responsible party has an SSN or ITIN, the IRS online EIN application gives you the number in the same session. Form SS-4 is for applying by fax or mail, for applicants who can’t use the online tool (for example, a responsible party with no SSN or ITIN), and for keeping a signed record of what you filed.
How long does it take to get an EIN with Form SS-4?
The IRS says about four business days by fax if you include a return fax number, and about four weeks by mail. International applicants can also apply by phone.
Who is the “responsible party” on line 7a?
The person who ultimately owns or controls the entity, or who directs how its funds and assets are used. Unless the applicant is a government entity, the responsible party must be an individual, not another company, and line 7b takes that person’s SSN, ITIN or EIN.
Where do I send Form SS-4?
Fax or mail it to the IRS EIN Operation. Applicants with a principal place of business in the US have mailed it to Internal Revenue Service, Attn: EIN Operation, Cincinnati, OH 45999. Check the “Where to File or Fax” table in the current Instructions for Form SS-4 before you send it, as numbers and addresses change.
Do I need a new EIN if I change my business name?
No. The form itself says not to apply for a new EIN if the entity only changed its name or elected on Form 8832 to change how it is taxed. You generally need a new EIN when the ownership or legal structure changes, such as a sole proprietor incorporating.
How to fill out Form SS-4, line by line
Line 1: the legal name of the entity or individual, exactly as on its formation papers. Line 2: trade name or “doing business as” name, if different. Line 3: executor, administrator, trustee or “care of” name, for estates and trusts. Lines 4a–4b: mailing address. Lines 5a–5b: street address, if different (not a P.O. box). Line 6: county and state of the principal place of business. Lines 7a–7b: the responsible party’s name and SSN, ITIN or EIN. Lines 8a–8c: whether the applicant is an LLC, how many members it has and whether it was organized in the US. Line 9a: type of entity (one box). Line 9b: state or country of incorporation, for corporations. Line 10: the reason for applying (one box). Line 11: the date the business started or was acquired. Line 12: closing month of the accounting year, which is December for most small businesses. Line 13: the highest number of employees expected in the next 12 months. Line 14: tick if you expect $1,000 or less in employment tax for the year and want to file Form 944 once a year instead of Form 941 every quarter. Line 15: first date wages were or will be paid. Lines 16–17: principal activity and main product or service. Line 18: whether the entity has had an EIN before.
Which lines you need
Page 2 of the form has a table for this. A new business with no employees completes lines 1, 2, 4a–8a, 8b–c if it is an LLC, 9a, 9b if it is a corporation, 10–14 and 16–18. A business that is hiring completes lines 1, 2, 4a–6, 7a–b, 8a, 8b–c and 9b where they apply, 9a and 10–18. If you only need an EIN to open a bank account, complete lines 1–5b, 7a–b, 8a, 8b–c and 9b where they apply, 9a, 10 and 18.
LLCs on Form SS-4
An LLC answers “Yes” on line 8a and gives its number of members on 8b. On line 9a, a multi-member LLC normally ticks Partnership, and a single-member LLC that hasn’t elected to be taxed as a corporation ticks “Other” and writes that it is a disregarded entity. An LLC that has elected corporate tax treatment ticks Corporation and enters the return it will file (Form 1120 or 1120-S). The instructions for line 9a set out each case.
Third party designee and signature
Complete the Third Party Designee section only if you want someone else, such as an accountant, to receive the EIN and answer questions about the form. The applicant must still sign and date the form. Someone other than the applicant can sign only if they are authorized, for example an officer of a corporation or a partner in a partnership.
Your details stay private
Form SS-4 asks for a Social Security number or ITIN. Everything you type stays in your browser: nothing is uploaded to ModifyPDF or stored after you close the page. This page provides the official form and general information, not tax advice; see the Instructions for Form SS-4 on irs.gov or ask a tax professional if you are unsure.