IRS Form SS-4: How to Apply for an EIN, Line by Line (2026)
IRS Form SS-4 is the one-page application you use to get an Employer Identification Number (EIN) for your business — and it is always free directly from the IRS. This guide walks through every line of the form, shows you the fastest way to submit it, and helps you avoid the mistakes that get applications rejected. Use the method finder below to see whether you should apply online, by fax, by mail, or by phone.
Written & verified by Ahmad Adil, LLC School · Updated June 2026
What Is IRS Form SS-4?
IRS Form SS-4, "Application for Employer Identification Number," is the official one-page form you use to request an EIN from the Internal Revenue Service. An EIN is a nine-digit number (formatted like 12-3456789) that identifies your business for federal tax purposes — essentially a Social Security Number for your company.
You'll need the EIN that IRS Form SS-4 generates to open a business bank account, hire employees, file business tax returns, run payroll, and apply for business credit. Most LLCs, corporations, and partnerships are required to have one.
The single most important thing to know: applying with IRS Form SS-4 is completely free when you go directly to the IRS. Any website charging a "filing fee" for an EIN is charging you for something the government gives away at no cost.
Never pay for an EINThe EIN itself is always $0 at IRS.gov. Third-party sites that advertise "EIN filing services" for $50–$300 are simply charging you to fill out a free form. The only legitimate cost is your time — and this guide removes most of that. See our full EIN number guide for the complete walkthrough.
Who Needs to File IRS Form SS-4?
You generally need to file IRS Form SS-4 (or apply online, which uses the same questions) if any of the following apply to your business:
- You formed an LLC with more than one member, or any LLC that will hire employees
- You have a single-member LLC and want to keep your SSN off business paperwork (strongly recommended)
- You'll open a business bank account, run payroll, or hire employees
- Your LLC will elect to be taxed as an S-Corp or C-Corp
- You're forming a corporation, partnership, trust, estate, or nonprofit
Form your LLC firstRegister your LLC with your state before you file IRS Form SS-4. The form asks for your legal entity name exactly as it appears on your formation documents, so the entity needs to exist first. One exception: sole proprietors with no employees can often use their SSN instead of an EIN.
IRS Form SS-4 Filing Method Finder
There are four ways to submit IRS Form SS-4 — and the right one depends on your situation. Answer three quick questions to see your fastest route, with the exact link, fax number, or phone number you need.
One EIN per responsible party, per dayNo matter which method you use, the IRS limits EIN issuance to one per responsible party each day. This applies across online, fax, mail, and phone. If you're setting up multiple entities, space out your applications.
IRS Form SS-4 Instructions — Line by Line
Here's exactly what each line on IRS Form SS-4 asks for and what to enter. The form is one page with roughly 18 numbered lines:
Legal Name of Entity
RequiredYour business's exact legal name as it appears on your formation documents (Articles of Organization, etc.). The IRS only accepts letters, numbers, hyphens, and ampersands — leave out other symbols.
Trade Name / DBA
OptionalEnter a trade name or "doing business as" name only if it's different from your legal name. If you operate under your exact legal name, leave this blank.
Executor, Trustee, "Care Of" Name
OptionalUsed mainly for trusts and estates. Most LLCs leave this blank unless mail should go to a specific third party.
Mailing Address
RequiredThe address where the IRS should send correspondence. A P.O. box is acceptable here. International applicants enter their foreign address.
Street Address
If differentYour physical business location, only if it differs from the mailing address. No P.O. boxes on this line.
County & State of Principal Business
RequiredThe county and state where your business is primarily located.
Responsible Party Name + SSN/ITIN/EIN
RequiredThe responsible party is the individual who ultimately owns or controls the entity — for most small businesses, that's you, the owner. It must be a person, not another company, and nominees are not allowed. Enter their name on 7a and SSN, ITIN, or EIN on 7b.
LLC Information
If LLCCheck "Yes" if the applicant is an LLC, enter the number of members, and indicate whether the LLC was organized in the United States. A two-member LLC defaults to partnership taxation; a single-member LLC defaults to a disregarded entity.
Type of Entity
RequiredCheck the box matching your federal tax classification. A single-member LLC usually checks "Other" and writes "Disregarded entity"; a multi-member LLC checks "Partnership." If you'll elect corporate taxation, indicate that here.
Reason for Applying
RequiredWhy you need the EIN — usually "Started new business." Other options include banking purposes, hiring employees, or a change in organization type.
Start Date, Accounting Year & Employees
RequiredLine 11: the date your business started or was acquired. Line 12: the closing month of your accounting year (usually December). Line 13: the highest number of employees you expect in the next 12 months — enter 0 if none.
Form 944, First Wages & Activity
As applicableLine 14: check this if you expect $1,000 or less in annual employment tax and want to file Form 944 yearly instead of quarterly. Line 15: first date wages were or will be paid. Line 16: your principal business activity (e.g., construction, retail, consulting).
Products/Services & Prior EIN
RequiredLine 17: a short description of your main product or service. Line 18: indicate whether this entity has ever applied for an EIN before — answer honestly to avoid duplicate-number issues.
Third-Party Designee & Signature
RequiredOptionally name a third-party designee authorized to receive the EIN and answer questions. Then the responsible party (or an authorized person) signs, dates, and prints their name, title, and daytime phone. For faxed forms, include a return fax number so the IRS can send your EIN back.
How to Submit IRS Form SS-4 (Online, Fax, Mail, Phone)
Once your IRS Form SS-4 is complete, here are your four submission channels and what to expect from each. Fax and phone numbers can change — always confirm the current ones on IRS.gov before you send.
The fastest option. Available to applicants in the US or US territories whose responsible party has a valid SSN, ITIN, or EIN. You get your EIN instantly on screen.
Best alternative when you can't apply online. The IRS faxes your EIN back to the return fax number on your form, so be sure to include one.
The slowest route. Complete the form 4–5 weeks before you need the EIN. Domestic applicants mail to the IRS service center listed in the SS-4 instructions.
Only for applicants whose principal business is outside the US. An IRS agent issues the EIN over the phone after verifying your answers.
International fax differs from domesticApplicants with no US residence fax IRS Form SS-4 to 855-215-1627 (within the US) or 304-707-9471 (from outside the US), and mail to the IRS EIN International Operation in Cincinnati, OH. Include a US fax number or phone where the IRS can return your EIN. Our EIN for foreign-owned LLC guide covers this in detail.
Common IRS Form SS-4 Mistakes to Avoid
- Paying a third party for a free EIN
- Listing a company (not a person) as responsible party
- Using a nominee instead of the real owner
- Applying before the LLC is registered with the state
- Choosing the wrong entity type on Line 9a
- Omitting the return fax number when faxing
- Applying for multiple EINs for one entity
- Apply free, directly at irs.gov/EIN
- Name a real individual as responsible party
- Form your LLC with the state first
- Match Line 9a to your actual tax treatment
- Include a return fax number on faxed forms
- File only one SS-4 per entity
- Save your EIN confirmation letter (CP 575)
Ahmad Adil's Take:If you have a US SSN or ITIN, skip the paper SS-4 entirely and apply online — it takes about 10 minutes and you walk away with your EIN the same day. The paper form really only matters for foreign owners without an SSN, who must fax it. And whatever you do, don't pay a "service" $200 to get a free number. The one thing worth delegating is the whole formation bundle: when I form through Northwest, the EIN is handled as part of the package, so the SS-4 questions, the responsible-party details, and the state filing all line up correctly the first time. Pay for the bundle and the privacy — never for the EIN alone.
- ✓Forms your LLC and can handle the SS-4 / EIN for you
- ✓$39 + state fee — Registered Agent free year 1
- ✓Your home address stays off public state records
- ✓No upsells · No data selling · $125/yr flat after year 1
Disclosure: LLC School may earn a commission via this link, at no cost to you. The EIN itself is always free at IRS.gov. See our advertising disclosure.
IRS Form SS-4 — FAQ
Ahmad Adil is the founder and CEO of LLC School. The line-by-line instructions, submission channels, fax numbers, and processing times in this guide were verified against the official IRS Instructions for Form SS-4 and the IRS Employer Identification Number pages as of June 2026. This guide is educational only — IRS phone and fax numbers can change, so always confirm current details on IRS.gov before filing.
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