How To Fill Out Form SS-4

Instructions for Tax Identification Applications

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Form SS-4 is an Internal Revenue Service (IRS) form used to apply for an employer identification number (EIN). An EIN is a nine-digit number used as an identifier for tax purposes by small businesses and other types of tax entities. 

Learn when you might need to have an employer ID number, how to complete IRS form SS-4 to apply for this number, and where to submit the form. 

Who Needs To Fill Out Form SS-4? 

Filling out an SS-4 form to get an Employer ID Number should be one of your first tasks when you start your small business or before you hire employees. You need an EIN if you:

  • Have employees or you are hiring employees for the first time
  • Operate your business as a corporation or a partnership 
  • Must pay employment taxes (Social Security and Medicare tax for employees, for example)
  • Must pay excise taxes or alcohol, tobacco, and firearms taxes
  • Withhold taxes on income, other than wages, paid to a non-resident alien
  • Have a Keogh plan 

Limited Liability Companies: A Special Case

A limited liability company (LLC) with one member (owner) is taxed as a sole proprietor, and LLCs with multiple members are taxed as partnerships. Some LLCs elect to be classified as a corporation or S corporation.

An LLC will need an EIN if it has employees or if it is required to file excise tax forms. A new single-member (owner) LLC will need an LLC. A single-member LLC that pays taxes using Schedule C and that doesn’t have employees doesn’t need an EIN. It should use the name and taxpayer ID of the owner for federal income tax purposes. 


Although it’s called an “employer” ID, an EIN may be required for other tax and legal purposes, including filing a federal income tax return for a small business. Banks and lenders require an EIN to open business bank accounts or apply for loans.

Instructions for Filling Out Form SS-4 

Form SS-4 has three main sections: general information, information about your business type, and other business information. Here’s what you need to know about each section.

General Information

In the general information section, you complete basic facts about your company.

  • Line 1: The legal name of your business and the trade name, if different 
  • Line 2: The trade name of your business, the “doing business as (DBA) name,” sometimes called a “fictitious name” 
  • Line 4: The mailing address of your business
  • Line 3: Only required for trusts and estates   
  • Line 7a and 7b: Information about the responsible party for your business and their tax ID number


The responsible party is the person who owns or controls the business or exercises ultimate effective control over the entity. It must be an individual (a natural person), not an entity (a business, for example). 

Business Type 

The second section of form SS-4 asks for details about the type of business you are filing for.

  • Lines 8a, 8b, and 8c: Whether the company is a limited liability company (LLC), the number of LLC members, and whether it was organized in the US. 
  • Lines 9a and 9b: Your business legal type. Line 9b is for corporations, to designate where the corporation was formed (in a U.S. state or foreign country).

If your business is a single-owner LLC, check the “Sole Proprietor” box and enter your Social Security number.

If your business is a multiple-owner LLC, check the “Partnership” box. 

If your business is a corporation and you have elected to be taxed as a corporation or an S corporation, check the “Corporation” box. You will also have to enter the correct tax form: Form 1120 for corporations and Form 1120-S for S corporations.


If your business is an LLC that has elected to be taxed as a corporation or S corporation before filling out Form SS-4, you may need to enter the “Corporation” box. Check with a licensed tax professional before you complete this section.

Other Information 

Finally, the last portion of SS-4 asks for more details about what you are applying for an EIN. Don’t apply if you already have an EIN and you are only adding another business location or you are hiring employees, not making some other change to your business.

  • Line 10: Your reason for applying. Check the appropriate box. Choices range from starting a new business to creating a pension plan.
  • Line 11: Date business started or acquired. Enter the appropriate date.
  • Line 12: Closing month of your business accounting year. For example, many businesses use Dec. 31 as a closing date. 
  • Line 13: Highest number of employees expected in the next 12 months. If you don’t expect to hire employees, enter “0” in the appropriate box.
  • Line 14: Do you want to file IRS Form 944? This form is for small businesses that have few employees and that expect to pay less than $1,000 in employment taxes in a calendar year. You can check the box on Line 14 to elect to use this form instead.
  • Line 15: First date wages or annuities were paid. If you have employees, enter the date when you expect to begin to pay wages. If you don’t plan to have employees, enter “N/A.” 
  • Line 16: The principal activity of the business. If you aren’t sure how to classify your business, the Instructions for Form SS-4 publication has a list of descriptions of the various business activity types. 

The information you provide on Form SS-4 has tax implications for your business. If you are unsure of how to answer any of the questions, get help from a licensed tax professional or tax attorney. 

How To File Form SS-4 for the EIN Application

There are several ways to file your EIN application. You can submit an online application to receive your EIN immediately. You can also apply by fax or by mail. The phone application option is only available to international applicants.


Before you begin an online application, consider printing a copy of Form SS-4 and entering all the information. It will make the online filing process faster, and you won’t have to worry about the IRS link timing out. 

Frequently Asked Questions (FAQs)

How do you fill out Form SS-4 for an LLC?

The IRS doesn’t consider limited liability companies (LLCs) as taxing entities. By default, single-member (owner) LLCs are considered as sole proprietors, and entities with multiple owners are considered partnerships.

Use Lines 8a-8c of Form SS-4 to enter information about the LLC. Then use the appropriate box on Line 9a to enter the information about your LLC.

Where do I fax my Form SS-4?

You can send Form SS-4 by fax and you generally receive your Employer ID Number within four business days. If your business is located in a U.S. state or the District of Columbus, the fax number is 855-641-6935.

Otherwise, the fax number is 855-215-1627 (if you are faxing from within the U.S.) or 304-707-9471 (if you are faxing from outside the U.S.) 

How do you get a copy of your Form SS-4?

If you want a copy of your SS-4 form, contact the IRS at the Business and Specialty Tax Line at 1-800-829-4933 Monday through Friday. 

If you don’t know your EIN, you may also be able to get it from one of several places: the IRS notice from when you applied; a bank you used to open a bank account or apply for a loan; or a state or local licensing agency. Your previous year’s tax return may also include your EIN.

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  1. IRS. “Do You Need an EIN?

  2. IRS. “Instructions for Form SS-4.” Page 3.

  3. Small Business Administration. “Open a Business Bank Account.”

  4. IRS. “Form SS-4.”

  5. IRS. “Lost or Misplaced Your EIN?”

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