formli AI logo formli AI
Back to Library
🇺🇸 United States

SS-4 Employer ID Number

EIN Application for Businesses

Easy ~10 min TaxBusinessEINLLC

/ What is this form?

Form SS-4, Application for Employer Identification Number, is the IRS form used to obtain an Employer Identification Number (EIN) — a 9-digit number (format: XX-XXXXXXX) that identifies a business entity for federal tax purposes. The EIN is sometimes called a Federal Tax Identification Number (FTIN) or Federal Employer Identification Number (FEIN).

An EIN is required for virtually any business activity: opening a business bank account, hiring employees, filing business tax returns, applying for business licenses, forming a partnership or corporation, and creating certain trusts or estates. Even sole proprietors who have no employees often need an EIN to separate personal and business finances or to avoid giving out their Social Security Number to clients.

The SS-4 can be filed online (instant), by fax (4 business days), by mail (4-5 weeks), or by phone (international applicants). The online application is by far the most efficient — the IRS issues the EIN immediately at the end of the online session. The paper SS-4 is used when online application is not available or preferred.

/ Who needs this form?

  • New LLCs, corporations, partnerships, and any multi-member business entities
  • Sole proprietors hiring their first employee
  • Sole proprietors who want to use an EIN instead of their SSN for privacy
  • Non-profit organizations applying for tax-exempt status
  • Estates of deceased individuals that will file a federal estate tax return or hire someone to manage the estate
  • Trusts that are required to file a separate tax return

/ What you need before you start

Full legal name of the business entity (exactly as filed with the state for LLCs and corporations)
Trade name or DBA (if applicable)
Name and Social Security Number (or ITIN) of the responsible party
Business mailing address
Type of entity and number of members (for LLCs)
Date business started and principal activity/product
Highest number of employees expected in the next 12 months

/ Step-by-step guide

1 Complete Lines 1–6 – Entity Information
Enter the legal name of the business exactly as registered with the state (Line 1), trade name or DBA if different (Line 2), the responsible party's name and SSN (Lines 7a and 7b), mailing address, county, and state where business is located.
2 Line 8–9 – Entity Type
Check one box for the type of entity: Sole proprietor, Partnership, Corporation, S corporation, Personal service corporation, Church or church-controlled, Other nonprofit, Other. For LLCs, enter the number of members on Line 8b. The entity type determines how the EIN is categorized and which tax returns you'll be required to file.
3 Line 10 – Reason for Applying
Select the primary reason you need an EIN: Started new business, Hired employees, Banking purpose, Changed type of organization, Purchased going concern, Created a trust, Created a pension plan, Other. This affects IRS categorization but not the EIN itself.
4 Lines 11–16 – Business Details
Enter the date business started or was acquired, the closing month of your accounting year (December for most), the highest number of employees expected in the next 12 months, whether you've ever had an EIN before, and the principal business activity and product or service.
5 Apply and Receive Your EIN
The fastest method is online at irs.gov — you receive your EIN immediately upon submission and can use it the same day. Alternatively, fax the completed SS-4 for a 4-business-day turnaround, or mail it for a 4–5 week wait. International applicants without a US presence must call the IRS international line.

/ Key fields explained

Field What to enter Common mistake
Line 1 – Legal Name The exact legal name of the entity as it appears in your state formation documents — for LLCs and corporations. For sole proprietors: your personal full name. Entering the trade name (DBA) on Line 1 instead of the legal entity name — the DBA goes on Line 2.
Line 8 – LLC Information Check 'Limited liability company' and enter the number of members. 1 member = single-member LLC. 2+ members = multi-member LLC. Leaving the number of LLC members blank — the IRS uses this to determine whether to classify the LLC as a disregarded entity (1 member) or partnership (2+ members) by default.
Line 9a – Type of Entity Check the one box that best describes your entity type. For LLCs, this is typically 'Limited liability company' — not 'Sole proprietor' even for single-member LLCs. Single-member LLC owners checking 'Sole proprietor' on Line 9a — technically a single-member LLC is a separate legal entity from its owner, even if taxed as a disregarded entity.
Line 10 – Reason for Applying Select the primary reason: 'Started new business' for most applicants. 'Banking purpose' if you only need it for a bank account. 'Hired employees' if that's the trigger. Selecting 'Hired employees' when you haven't hired anyone yet — this causes the IRS to expect Form 941 (payroll tax) filings.

/ Common mistakes to avoid

Applying for a new EIN when the business already has one — check old tax returns or call the IRS Business and Specialty Tax Line (1-800-829-4933).
Using an entity name rather than an individual as the responsible party on Lines 7a/7b — the IRS requires an individual with an SSN or ITIN since 2014.
Applying multiple times because the confirmation was lost — this can create duplicate EINs which cause IRS processing issues.
Not applying online when possible — the paper form takes 4-5 weeks by mail while the online application is instant.
Selecting the wrong entity type on Line 9a — this affects which tax forms the IRS expects you to file annually.

/ Frequently asked questions

Does a single-member LLC need an EIN?

Not always for tax purposes — a single-member LLC can use the owner's SSN if it has no employees and doesn't file excise taxes. However, most banks require an EIN to open a business account, so practical purposes usually make an EIN necessary.

How long does it take to get an EIN?

Online: immediate — you receive the EIN at the end of the session. By fax: 4 business days. By mail: 4-5 weeks. International phone: you receive it at the end of the call.

Can I apply for an EIN if I don't have an SSN?

You need either an SSN or an ITIN to apply online or by phone. If you have neither, you must file the paper SS-4 and include an explanation. International applicants without a US tax ID must call the IRS International line: 267-941-1099.

Is the EIN the same as the state tax ID number?

No. The EIN is a federal IRS number. Most states have a separate state tax identification number for state income tax and sales tax purposes. You may need to register separately with your state revenue department.