To fill out Form SS-4, you enter your entity’s legal name and address, name a responsible party with their taxpayer ID, choose your entity type and reason for applying, describe your employment and business activity, sign, and submit. The form is free through every IRS channel, and applying online at irs.gov returns your Employer Identification Number in minutes.
Before You Start the Form
If you’re forming an LLC, corporation, partnership, or tax-exempt organization, finish your state registration first. The IRS warns that applying before state formation is complete can delay your application.1Internal Revenue Service. Get an Employer Identification Number
To use the online application, the responsible party must have a valid taxpayer identification number (SSN, ITIN, or existing EIN) and a legal residence or principal place of business in the United States or a U.S. territory. Applicants without a U.S. address cannot use the online system and must apply by phone, fax, or mail.2Internal Revenue Service. Instructions for Form SS-4
Gather your entity’s legal name exactly as it appears on your state formation certificate, any trade name or DBA, the mailing and street addresses, the formation or acquisition date, and the responsible party’s name and taxpayer ID. Have this in front of you before you begin, because the online application will time out if you leave it idle.
Line-by-Line: Filling Out Form SS-4
The current version of Form SS-4 was revised in December 2025. The paper form and the online interview ask the same questions.
Lines 1–6: Entity Name and Address
Line 1 is the entity’s legal name, exactly as it appears on your state registration documents. Mismatches here are one of the most common reasons applications hit trouble. If your state certificate says “Smith Consulting LLC,” write “Smith Consulting LLC,” not “Smith Consulting.” Line 2 is for a trade name or DBA if it differs from the legal name. Lines 3 through 6 collect the mailing address and, if different, the physical street address.3Internal Revenue Service. About Form SS-4
Lines 7a–7b: Responsible Party
Every entity must name one responsible party: the individual who owns, controls, or manages the entity and its finances. Line 7a is that person’s name; Line 7b is their SSN, ITIN, or EIN. For a corporation, this is typically the principal officer. For a partnership, a general partner. For a trust, the grantor or trustor.4Internal Revenue Service. Responsible Parties and Nominees
If the responsible party ever changes after your EIN is issued, you have 60 days to notify the IRS on Form 8822-B.5Internal Revenue Service. About Form 8822-B, Change of Address or Responsible Party – Business
Lines 8–10: Entity Type and Reason for Applying
Line 8 asks you to select the entity’s legal classification: corporation, partnership, sole proprietor, estate, trust, or a specific LLC type. Selecting a classification here does not elect S-corporation tax status. If you want your corporation or eligible LLC treated as an S-corp, file a separate Form 2553.6Internal Revenue Service. About Form 2553, Election by a Small Business Corporation
Line 9 is the reason you’re applying: starting a new business, hiring employees, banking purposes, or a change in organizational structure, among others. Line 10 is the start date of the business or the date you acquired it.
Lines 11–17: Accounting Year, Employees, and Activity
Line 12 asks for the highest number of employees you expect over the next 12 months, split into three categories: agricultural, household, and other. If you don’t plan to hire, enter zero. Line 13 asks for the date you first paid or expect to pay wages. Line 14 asks the closing month of your accounting year, which is December for most businesses.3Internal Revenue Service. About Form SS-4
Line 17 asks you to describe the entity’s principal business activity. Be concrete. “Retail sale of clothing” or “residential plumbing services” reads better than “consulting” or “services.”
Line 18: Third Party Designee
If an attorney, accountant, or other person is handling the application for you, Line 18 authorizes them to receive the EIN and answer IRS questions about the form. The authorization is narrow: it ends the moment the EIN is assigned and released to the designee, and it does not extend to any other tax matter.7Internal Revenue Service. Instructions for Form SS-4
An authorized individual must sign and date the form for it to be valid, whether you’re submitting on paper or completing the online interview.
How to Submit the Form
The IRS offers the EIN application at no charge through every method. You should never pay for an EIN. The FTC has warned consumers about websites that mimic the IRS and charge up to $300 for what is a free service, sometimes using IRS logos, colors, or the phrase “EIN Assistant” to look official. If a site asks for payment, you are not on irs.gov.8Federal Trade Commission. Don’t Pay to Get Your Employer Identification Number (EIN)
Online
The online application walks you through an interview-style questionnaire and issues your EIN immediately once the answers validate. Hours are limited: Monday through Friday, 6:00 a.m. to 1:00 a.m. the next day; Saturday, 6:00 a.m. to 9:00 p.m.; Sunday, 6:00 p.m. to midnight, all Eastern Time. Only one EIN per responsible party per day is allowed through the online system.1Internal Revenue Service. Get an Employer Identification Number
Fax
Fax the completed paper Form SS-4 to 855-641-6935. If you include a return fax number, the IRS will fax back a confirmation with your EIN in about four business days.9Internal Revenue Service. Employer Identification Number
Mail the completed form to Internal Revenue Service, Attn: EIN Operation, Cincinnati, OH 45999. Expect roughly four weeks.9Internal Revenue Service. Employer Identification Number
Phone (International Applicants Only)
If you have no legal residence or principal business in the United States, apply by phone at 267-941-1099 (not toll-free), Monday through Friday, 6:00 a.m. to 11:00 p.m. Eastern Time. An IRS representative walks you through the questions and assigns the EIN during the call.2Internal Revenue Service. Instructions for Form SS-4
Common Errors and How to Fix Them
The most frequent problem with online submissions is a name mismatch. If the legal name you enter conflicts with what the IRS already has on file for the responsible party, or too closely matches an existing entity’s name, the system returns Reference Number 101 and stops.
To resolve it, call the IRS at 800-829-4933. A representative will typically ask you to fax in your completed SS-4 along with a copy of your filed certificate of incorporation or formation, and the paper route usually clears the issue within a few business days.
Another frequent mistake is leaving “LLC” off the legal name when your state formation documents include it. The IRS needs the business name to match state registration exactly. If you’ve already received an EIN with the wrong name, send a written correction to the IRS that includes your EIN, the correct legal name as shown on your state certificate, and a brief note that you are correcting the name for tax reporting.
What You Get Back
When the IRS approves your application, it issues a CP 575 notice, the official EIN confirmation letter. This is the only time the IRS sends this particular notice, and the agency will not reissue it. Store it with your formation documents.
If you lose the CP 575 later, you can request a 147C verification letter by calling the IRS business line at 800-829-4933. Banks, payroll providers, and government agencies accept the 147C as equivalent proof. You can receive it by fax during the call, or by mail in four to six weeks.
Your EIN is now ready for opening a business bank account, filing federal tax returns, reporting employment taxes, and providing to vendors who request a W-9. Once assigned, the number stays with your entity for its entire existence and cannot be transferred to another business.