Form SS-4: Get Your Employer Identification Number (EIN)
Apply for your business tax ID online in 2026. Fill out IRS Form SS-4 for instant EIN issuance — free, secure, and ready to fax or mail to the IRS.
What is Form SS-4?
The official IRS application for your business tax ID
Form SS-4 (Application for Employer Identification Number) is the official IRS form used to obtain an EIN (Employer Identification Number) — a unique 9-digit tax ID number for your business. Think of it as a Social Security number for your business: it's used for tax filings, hiring employees, opening business bank accounts, and establishing business credit.
While most U.S. business owners can get an EIN instantly through the IRS online application, Form SS-4 is essential for international applicants, third-party designees (accountants/lawyers applying on behalf of clients), and foreign business owners without a U.S. Social Security number or ITIN.
Who Needs an EIN?
When you must apply for a business tax ID
EIN Required
- All corporations (C corp and S corp)
- All partnerships (including multi-member LLCs)
- Any business with employees
- Businesses filing employment tax returns
- Businesses filing excise tax returns
- Trusts (except certain grantor trusts)
- Estates of deceased persons
- Nonprofit organizations
- Businesses withholding on nonresident aliens
- Qualified retirement plans (401k, SEP IRA)
EIN Optional (But Recommended)
- Sole proprietors with no employees
- Single-member LLCs with no employees
- Banks require it for business accounts
- Protects your SSN from identity theft
- Establishes business credit separate from personal
- Prepares for hiring employees later
- Looks professional with clients and vendors
How to Get Your EIN in 2026
Four ways to apply — online is fastest
Online Application (Recommended)
- Processing: Instant (5 minutes)
- Cost: Free
- Where: IRS.gov/EIN
- Requirement: SSN or ITIN + U.S. location
- Hours: Mon-Fri 6am-1am ET, Sat 6am-9pm ET
Fax Form SS-4
- Processing: 4 business days
- Cost: Free
- U.S. fax: 855-641-6935
- International: 304-707-9471
- Available: 24/7
Phone (International Only)
- Processing: Instant (during call)
- Cost: Free (not toll-free)
- Phone: 267-941-1099
- Hours: Mon-Fri 6am-11pm ET
- Note: Non-U.S. applicants only
Mail Form SS-4
- Processing: 4-5 weeks
- Cost: Free
- Address: IRS, EIN Operation, Cincinnati OH 45999
- Status check: 800-829-4933
- Tip: Sign and date before mailing
Important: An EIN is always free from the IRS. Avoid third-party websites charging $50-300 — they're unnecessary middlemen. Apply directly at IRS.gov/EIN or use our free Form SS-4 tool.
How to Complete Form SS-4
Step-by-step instructions for your EIN application
Legal Business Name (Line 1)
- Sole proprietors: Your personal legal name (e.g., "Jennifer Smith"), not your business name
- LLCs: Full legal name with "LLC" (e.g., "Smith Consulting LLC")
- Corporations: Corporate name with suffix (e.g., "Smith Consulting, Inc.")
- Partnerships: Name from partnership agreement
- Trusts: Name from trust instrument
- Estates: "[Deceased Name] Estate"
Trade Name & Contact Info (Lines 2-6)
- Line 2: "Doing Business As" (DBA) name if different from legal name
- Line 3: Care-of name (trustee, executor, or designated person)
- Lines 4a-4b: Mailing address for IRS correspondence
- Lines 5a-5b: Physical business address (no P.O. box)
- Line 6: County and state where business is physically located
Responsible Party (Lines 7a-7b)
Enter the name and SSN (or ITIN) of the individual person who ultimately owns or controls the business. Must be a real person, not another entity.
- Sole proprietor: You (the owner)
- LLC: Managing member or majority owner
- Corporation: President, CEO, or principal officer
- Partnership: General partner
- Trust: Grantor, owner, or trustor
- Estate: Executor or administrator
Entity Type & Reason (Lines 8-10)
- Line 8: If LLC, check "Yes" and enter member count
- Line 9a: Check your entity type — sole proprietor, corporation, partnership, trust, estate, other nonprofit, or "other" (write "disregarded entity" for single-member LLC)
- Line 9b: If corporation, specify "1120" (C corp) or "1120-S" (S corp)
- Line 10: Reason for applying — started new business, hired employees, banking purpose, changed organization, purchased business, created trust, or other
Business Details (Lines 11-17)
- Line 11: Date business started or acquired
- Line 12: Closing month of accounting year (usually December)
- Line 13: Number of employees expected in next 12 months (enter 0 if none)
- Line 14: Check if you want to file Form 944 annually (for employers owing ≤$1,000/year in employment taxes)
- Line 15: First date wages were paid or will be paid (or "N/A" if no employees)
- Lines 16-17: Principal business activity category and detailed description
Sign and Submit (Line 18 & Signature)
- Line 18: Check whether entity has previously applied for an EIN
- Third-party designee: Complete only if your accountant or lawyer should receive the EIN
- Signature: Owner (sole prop), president (corp), authorized partner (partnership), or fiduciary (trust/estate)
- Submit by fax: 855-641-6935 (U.S.) — receive EIN in 4 business days
- Submit by mail: IRS, Attn: EIN Operation, Cincinnati, OH 45999 — 4-5 weeks
EIN Guidance by Business Type
How to fill out Form SS-4 for your specific entity
Sole Proprietors
Line 1: your personal name. Line 2: business/trade name. Line 9a: check "Sole proprietor." An EIN is optional if you have no employees, but recommended for banking and SSN protection. You can operate multiple businesses under one EIN.
Single-Member LLC
Line 1: LLC legal name. Line 8a: "Yes," Line 8b: "1." Line 9a: check "Other" and write "Disregarded entity." The IRS treats single-member LLCs as pass-through entities — you'll report income on Schedule C with your personal Form 1040.
Multi-Member LLC / Partnership
EIN is always required. Line 1: LLC/partnership legal name. Line 8a: "Yes," Line 8b: number of members. Line 9a: check "Partnership." You'll file Form 1065 annually and issue Schedule K-1s to each member.
Corporation (C Corp / S Corp)
EIN is always required. Line 1: corporate name with suffix (Inc., Corp.). Line 9a: check "Corporation" and specify "1120" (C corp) or "1120-S" (S corp). For S corp election, get your EIN first, then file Form 2553 within 2 months + 15 days of your tax year start.
Trusts, Estates & Nonprofits
Trusts: Line 1 = trust name, Line 3 = trustee, Line 9a = "Trust." Estates: Line 1 = "[Name] Estate," Line 9a = "Estate" with deceased's SSN. Nonprofits: Get your EIN first, then file Form 1023/1024 for tax-exempt status — getting an EIN doesn't make you tax-exempt.
When You Need a New EIN (vs. Keeping Your Current One)
Certain business changes require a new EIN — others don't
You Need a New EIN
- Sole proprietorship incorporates (new legal entity)
- You take on a partner (sole prop → partnership)
- Partnership incorporates (→ corporation)
- You purchase or inherit a business and change its structure
- 50%+ ownership changes in a partnership within 12 months
- Corporation undergoes bankruptcy reorganization
Keep Your Current EIN
- Change your business name (file Form 8822-B)
- Change your business address (file Form 8822-B)
- Elect or terminate S corp status (same EIN)
- Partners join or leave (unless 50%+ changes)
- Business becomes inactive (reuse EIN later)
- Change responsible party (file 8822-B within 60 days)
Common SS-4 Mistakes to Avoid
Don't let these errors delay your EIN
Applying Before State Registration
Register your LLC or corporation with your state first. The IRS verifies your legal entity name matches state records.
Using DBA Name on Line 1
Line 1 is your legal name, not your trade/DBA name. Sole proprietors enter their personal name. Put the DBA on line 2.
Wrong Entity Type on Line 9a
Single-member LLC → "Other (disregarded entity)." Multi-member LLC → "Partnership." Getting this wrong means filing the wrong tax returns.
Not Saving EIN Confirmation
Print or screenshot the online confirmation immediately. The IRS doesn't email it, and the CP 575 mail letter takes 4-6 weeks to arrive.
Paying for an "EIN Service"
The IRS EIN application is always free. Never pay $50-300 to a third-party website — go directly to IRS.gov/EIN.
Duplicate EIN Applications
Use only one method. Don't apply online and then mail Form SS-4 — this creates duplicate EIN records and tax filing confusion.
Special Situations
International applicants, trusts, estates, and more
Foreign Business Owners (No SSN/ITIN)
Write "foreign" or "N/A" on line 7b. Submit Form SS-4 by fax (855-215-1627 U.S. callers / 304-707-9471 international) or call 267-941-1099 Mon-Fri 6am-11pm ET for instant EIN by phone. You cannot use the IRS online tool without a valid SSN or ITIN.
EIN Applied For, But Not Received?
If a tax return is due before you receive your EIN, write "Applied For" and the date you applied in the EIN field. Don't use your SSN as an EIN. Call 800-829-4933 to check status of mailed applications.
Third-Party Designee (Accountant/Lawyer)
Complete the "Third-Party Designee" section at the bottom of Form SS-4. The client must sign the form. The IRS will release the EIN to the designee — their authority ends once the EIN is assigned. The CP 575 confirmation letter is still mailed to the client.
Frequently Asked Questions
Common questions about EIN applications and Form SS-4
Is an EIN free?
Yes, completely free. The IRS never charges for an EIN. Avoid third-party websites charging $50-300 to "help" you get one — they're unnecessary. Apply directly at IRS.gov/EIN (online, instant) or use our free Form SS-4 fillable PDF tool to prepare your application for fax or mail submission.
How long does it take to get an EIN?
Online at IRS.gov/EIN: instant (5 minutes). Fax Form SS-4: 4 business days. Phone (international applicants only, 267-941-1099): instant during the call. Mail Form SS-4 to Cincinnati: 4-5 weeks. For U.S. business owners with an SSN or ITIN, the online tool is the fastest method.
Does my single-member LLC need an EIN?
Not technically required if you have no employees and no excise tax liability. However, nearly all banks require an EIN to open a business bank account for an LLC. Getting one also protects your SSN, helps establish business credit, and prepares you for future hiring. It's free and takes 5 minutes — there's no reason not to get one.
How long is an EIN valid?
An EIN is permanent and never expires. Once issued, it's yours forever — even if you close your business. If you reopen the same business later (same structure and owner), you can reuse your old EIN. You never need to "renew" an EIN.
Can I get an EIN on weekends?
Yes, but with limited hours. The IRS online tool is available Saturday 6:00 a.m. to 9:00 p.m. ET and Sunday 6:00 p.m. to 12:00 a.m. ET. You can also fax Form SS-4 anytime (24/7), though the IRS processes faxes during business days only.
What if I make a mistake on my EIN application?
Minor errors (address typo, wrong business description): file Form 8822-B to correct your records. Major errors (wrong entity type, wrong legal name): call the IRS at 800-829-4933 immediately — you may need a new EIN. Once an EIN is assigned, you cannot change the legal name or entity type online.
Do I need separate EINs for multiple businesses?
Sole proprietors: no — you can operate multiple businesses under different trade names with one EIN. However, each separate legal entity (LLC, corporation, partnership) must have its own EIN. Divisions or branches of the same corporation use the parent company's EIN.
Can I use Form SS-4 if I'm outside the United States?
Yes. International applicants must use Form SS-4 (the online tool requires a U.S. location). Fax to 855-215-1627 (U.S. callers) or 304-707-9471 (international callers) for 4-day processing. Or call 267-941-1099 Mon-Fri 6am-11pm ET for instant EIN by phone. On line 7b, write "foreign" or "N/A" if you have no SSN/ITIN.
Ready to Get Your EIN?
Fill out Form SS-4 online using our free tool. Your completed form will be ready to fax or mail to the IRS.
Related Forms
Other forms you may need after getting your EIN
About Form SS-4 and EIN Applications
Form SS-4 (Application for Employer Identification Number) is the official IRS form used to obtain a business tax identification number. Millions of new businesses apply for EINs each year — from solo freelancers and single-member LLCs to large corporations and nonprofit organizations.
The IRS recommends applying online at IRS.gov/EIN for instant results. However, Form SS-4 remains the standard application method for international businesses, foreign-owned U.S. entities, and situations where a third-party designee (accountant or attorney) needs to receive the EIN on behalf of a client. The December 2025 revision of Form SS-4 updated the fax numbers and mailing addresses for EIN applications.
An EIN is permanent and never expires. Once assigned, it stays with your business for its lifetime — through name changes, address changes, and ownership transitions. Only structural changes to your legal entity (such as incorporating a sole proprietorship or terminating a partnership) require a new EIN application.
Our free online Form SS-4 tool provides the current official IRS form with an intuitive fillable interface. Whether you're starting a new business, hiring employees, forming an LLC, or establishing a nonprofit, our secure platform helps you complete SS-4 quickly and accurately. For a detailed guide, see our complete EIN application guide for 2026.