The SS4 form is Form SS-4, Application for Employer Identification Number, the Internal Revenue Service (IRS) form used to request an Employer Identification Number (EIN), the 9-digit number the IRS assigns to employers, sole proprietors, corporations, partnerships, estates, trusts and other entities for tax filing and reporting. You use it when the entity does not already have an EIN but must show one on a return, statement or other document. On FillingPDF you can fill out Form SS-4 online and download or print the completed PDF; the IRS publishes the official PDF and its instructions at irs.gov and recommends applying electronically when possible.
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What is SS-4?
Form SS-4, Application for Employer Identification Number, is the IRS form used to apply for an EIN, a 9-digit number (for example, 12-3456789) assigned to sole proprietors, corporations, partnerships, estates, trusts and other entities for tax filing and reporting purposes.
The information on the form establishes the entity's business tax account. The form is issued by the Department of the Treasury, Internal Revenue Service, under OMB No. 1545-0003. Page 1 holds the 18 lines, the Third Party Designee section and the signature block. Page 2 is a "Do I Need an EIN?" table that tells each type of applicant, such as a new business, an estate, a trust, a pension plan administrator, a withholding agent or a single-member LLC, which lines to complete.
An EIN is for business activities only. The IRS instructions say not to use it in place of a Social Security number (SSN) or Individual Taxpayer Identification Number (ITIN).
The form also carries the choices that depend on the entity: line 9a for the type of entity, line 10 for the reason for applying, and line 14 for employers who want to file Form 944 annually instead of Form 941 quarterly. The IRS publishes a Spanish-language version, Form SS-4 (sp). Form 8822-B, Change of Address or Responsible Party — Business, is the form used afterward to report changes; it is not part of this application.
Who needs to file SS-4?
File Form SS-4 if the applicant entity does not already have an EIN but is required to show one on a return, statement or other document. The "Do I Need an EIN?" table on page 2 lists the situations:
- a new business, including one that hired or will hire employees (household employees included);
- an entity that needs an EIN for banking purposes only;
- an organization that changed its type, for example by incorporating a sole proprietorship or forming a partnership;
- a purchaser of a going business that has no EIN;
- a trust other than a grantor trust or an IRA trust;
- a pension plan administrator who needs an EIN for reporting;
- a foreign person who needs an EIN to comply with IRS withholding regulations;
- an estate that must report income on Form 1041;
- a withholding agent that files Form 1042, and certain state or local agencies;
- a single-member LLC, or an S corporation that needs an EIN to file Form 2553.
A partnership, corporation, REMIC, nonprofit organization or farmers' cooperative must use an EIN for any tax-related purpose, even without employees.
Do not apply again if the entity only changed its business name, or if a partnership terminated because at least 50% of its interests were sold or exchanged within 12 months; its EIN stays the same. A sole proprietor generally files only one Form SS-4. For a trust, the signer is the fiduciary. The IRS issues only one EIN per responsible party per day.
When to file SS-4
File Form SS-4 when the entity needs an EIN and does not have one, for example when it starts a business, hires employees, changes its type of organization, buys a going business or creates a trust. If you apply by mail, complete the form at least 4 to 5 weeks before you will need the EIN.
If you do not have the EIN by the time a return is due, the IRS instructions say to write "Applied For" and the date you applied in the space for the number, and not to show your SSN as an EIN. An S corporation election on Form 2553 must be filed no later than the 15th day of the 3rd month of the tax year the election takes effect.
After you have an EIN, keep the information current: changes of responsible party must be reported to the IRS within 60 days on Form 8822-B. Processing times by channel are in the next section.
Documents you need
- The signed Form SS-4, including any third-party designee authorization, only if an IRS representative asks for it after an international telephone application; mail or fax it within 24 hours to the address the representative gives.
How to fill out SS-4
Enter the legal name and trade name
Line 1: the legal name of the entity or individual exactly as it appears on the Social Security card, charter or other legal document. Line 2: the trade name (DBA) only if different from line 1.
Add a care-of name if needed
Line 3: for a trust, enter the trustee; for an estate, the executor, administrator or other fiduciary; or enter a designated person to receive tax information.
Enter mailing and street addresses
Lines 4a and 4b: the mailing address for correspondence. Lines 5a and 5b: the physical address only if different, with no P.O. box. For foreign addresses, include the country name unabbreviated.
Give the county and state
Line 6: the county and state where the principal business is located, that is, its primary physical location.
Identify the responsible party
Line 7a: the full name of the responsible party, who must be an individual unless the applicant is a government entity. Line 7b: SSN, ITIN or EIN; enter "foreign" or N/A if the person has no SSN or ITIN and cannot obtain one.
Answer the LLC questions
Line 8a: check Yes or No for a limited liability company. If Yes, enter the number of members on line 8b and answer line 8c on whether it was organized in the United States.
Select the type of entity
Line 9a: check only one box and add the details it asks for, such as the return form number for a corporation. On line 9b, name the state or foreign country of incorporation if applicable.
State the reason for applying
Line 10: check only one box and specify where the box asks, for example the type of business started. Do not enter N/A here.
Enter dates and accounting year
Line 11: the date the business started or was acquired (month, day, year). Line 12: the closing month of the accounting year.
Complete employee information
Line 13: the highest number of Agricultural, Household and Other employees expected in the next 12 months, entering -0- if none. Line 14: check the box only if you qualify and want to file Form 944 annually; skip it if you expect no employees.
Enter the first wage payment date
Line 15: the date wages or annuities were first paid, or N/A if no employees are planned. Withholding agents enter the date income will first be paid to a nonresident alien.
Describe the business activity
Line 16: check the one box that best describes the principal activity, or Other and specify. Line 17: describe the principal line of merchandise, construction work, products or services; an entry is required.
Report any previous EIN
Line 18: check Yes or No for whether the entity has ever applied for and received an EIN. If Yes, write the previous EIN.
Complete the designee section if needed
Complete the Third Party Designee section only to authorize a named individual to receive the EIN and answer questions about the form: name, telephone, address and fax. The authorization is valid only if the signature area is completed.
Review, sign and download the PDF
Enter the applicant's telephone number, name and title, then sign and date. Use N/A on lines that do not apply, check every entry, then download or print the completed PDF from FillingPDF and keep a copy.
How to submit SS-4
The IRS accepts EIN applications online, by fax, by mail and, for international applicants only, by telephone. Use only one method for each entity, so that you do not receive more than one EIN.
- Online: the IRS recommends this method. Applicants with a legal residence, principal place of business or principal office or agency in the United States or U.S. territories apply at IRS.gov/EIN, where the EIN is issued immediately and there is no fee. The online tool is its own application, not this PDF.
- Fax: the EIN generally comes back by fax within 4 business days. From the 50 states or the District of Columbia, fax to 855-641-6935. Elsewhere, fax to 855-215-1627 (within the United States) or 304-707-9471 (outside it). Include your fax number.
- Mail: from the 50 states or the District of Columbia, send to Internal Revenue Service, Attn: EIN Operation, Cincinnati, OH 45999. Otherwise, send to Internal Revenue Service, Attn: EIN International Operation, Cincinnati, OH 45999. The EIN arrives by mail in about 4 weeks.
- Telephone (international applicants only): call 267-941-1099 (not toll-free), 6:00 a.m. to 11:00 p.m. Eastern time, Monday through Friday. If asked, mail or fax the signed form within 24 hours.
To verify a number or ask about the status of a mailed application, call 800-829-4933. FillingPDF lets you fill out and download the PDF; submission follows the channels above.
Common mistakes to avoid
- Using more than one method for the same entity, such as applying online and then mailing the form, which can produce more than one EIN.
- Entering a business name on line 1 when you are a sole proprietor; line 1 takes your individual name and the business name goes on line 2.
- Using abbreviations or nicknames on line 1 instead of the name exactly as it appears on the Social Security card, charter or other legal document.
- Listing an entity as the responsible party on line 7a when the applicant is not a government entity; it must be an individual, with an SSN or ITIN on line 7b.
- Entering a P.O. box on line 5a, or abbreviating the country name on a foreign address.
- Checking more than one box on line 9a or line 10, or writing "N/A" on line 10 or in the Other entry on line 9a.
- Checking only the LLC box type on line 9a without reading the instructions: a single-member LLC treated as a disregarded entity checks Other and writes "disregarded entity".
- Leaving line 17 blank; an entry is required and should describe the principal line of business in more detail than line 16.
- Applying for a new EIN when the entity only changed its business name.
- Faxing or mailing the form without a signature in the signature block.
Frequently asked questions
What is the SS4 form used for?
The SS4 form, Form SS-4, is the IRS application for an Employer Identification Number. You use it when an entity such as a business, estate, trust or plan administrator needs an EIN to show on a return, statement or other document and does not already have one.
Where can I get the SS4 form as a fillable PDF?
The IRS publishes the PDF at irs.gov, and its instructions note that the downloaded form is fillable and suitable for faxing or mailing. You can also fill out the PDF online on FillingPDF and download it; FillingPDF is independent of the IRS and does not submit the form.
Do I have to use Form SS-4 to get an EIN?
Not necessarily. The IRS recommends applying electronically if possible, and applicants in the United States or U.S. territories can get an EIN online at IRS.gov/EIN. Form SS-4 is used for the fax, mail and international telephone methods, and its page 2 shows which lines to complete.
Is there a fee to apply for an EIN?
The IRS says applicants in the United States or U.S. territories can apply and receive an EIN free of charge on IRS.gov, and that you never have to pay a fee for an EIN. Be careful with websites that charge for one.
How long does it take to get an EIN with Form SS-4?
By fax, the EIN generally comes back within 4 business days. By mail, you receive it in approximately 4 weeks, so the instructions advise completing the form at least 4 to 5 weeks before you need it. An online application issues the EIN immediately.
Where do I mail or fax Form SS-4?
From the 50 states or D.C., mail to Internal Revenue Service, Attn: EIN Operation, Cincinnati, OH 45999, or fax to 855-641-6935. Applicants without a legal residence or principal place of business in a state use the EIN International Operation address or the other fax numbers in the instructions.
Who signs Form SS-4?
The individual signs if the applicant is an individual. A corporation uses its president, vice president or other principal officer, and a partnership, government entity or other unincorporated organization uses a responsible, duly authorized member or officer. A trust or estate uses the fiduciary.
What is the difference between Form SS-4 and Form SS-4 (sp)?
Form SS-4 (sp) is the Spanish-language version of Form SS-4. Both are published by the IRS for the same purpose: applying for an EIN. This page covers the English-language Form SS-4, Rev. December 2025.
Can I apply for more than one EIN in a day?
No. EIN issuances are limited to one per responsible party per day, for all requests whether online, by telephone, fax or mail. For trusts the limit applies to the grantor, owner or trustor, and for estates to the decedent or the debtor.
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