How to Get an EIN in California: Online, Fax, or Mail

To get an EIN in California, apply directly with the IRS at no cost. The online EIN assistant is the fastest route and issues your nine-digit number the moment the application is approved; if you prefer paper, you can fax or mail Form SS-4 instead.¹ The IRS has warned that you never need to pay for an EIN, so be cautious of third-party sites that charge a fee to file on your behalf.

Do You Need an EIN

Most California LLCs, corporations, and partnerships need an EIN to hire employees, open a business bank account, or file federal and state tax returns. You are generally required to get one if you operate a partnership or corporation, hire employees, or file excise tax returns.¹

Sole proprietors without employees can often use their Social Security number for federal tax purposes. Even so, most still end up applying, because banks typically ask for an EIN to open a business account and some California business licenses require one.² Using an EIN also keeps your SSN off vendor paperwork and lets the business credit bureaus build a profile tied to the company rather than to you personally.³

What to Have Ready Before You Apply

Gather everything before you start. This matters most for the online application, which cannot be saved and resumed later and will time out after 15 minutes of inactivity.¹

The legal name of the entity, exactly as it appears on your California Articles of Organization or Articles of Incorporation, plus any DBA name you use publicly.⁴
A physical street address in California. The IRS does not accept a P.O. Box as the principal business location.⁴
Your entity type: sole proprietorship, LLC, corporation, partnership, trust, or other. LLC applicants also need to know the number of members and the federal tax classification they want.
The responsible party’s name and either their Social Security number or Individual Taxpayer Identification Number. The responsible party must be a real person with authority to control the entity’s finances, not another business. For a single-member LLC this is usually the owner; for a corporation it is typically a principal officer.⁵
Your reason for applying (starting a new business, hiring employees, creating a trust, and so on), the business start date, and the fiscal year you will use.

Keep your California Secretary of State file number nearby too. It is not entered on the federal form, but having it on hand helps you keep the federal and state records consistent.

If you expect your total employment tax liability to be $1,000 or less for the calendar year, which is roughly $5,000 or less in wages, you can elect on Line 14 to file Form 944 once a year instead of Form 941 every quarter.⁶

Applying Online (Fastest)

The IRS online EIN assistant walks you through the same fields as Form SS-4 in an interview format, then issues the number immediately on approval. To use it, your principal place of business must be in the United States, and the responsible party must have a valid SSN or ITIN. An ITIN holder can serve as the responsible party as long as the business operates in the U.S.⁷

The tool is available during these hours, all Eastern Time:¹

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

Finish the application in one session. If it sits idle for more than 15 minutes it expires and you start over.¹ At the end, you can download a confirmation on the spot, and the official CP 575 notice follows by mail.

Applying by Fax

Fill out Form SS-4 (the IRS posts it as a downloadable PDF)⁸ and fax it to (855) 641-6935. Put a return fax number on the form, and the IRS will fax your EIN back in about four business days.⁹

Applying by Mail

Mail the signed Form SS-4 to:

Internal Revenue Service
Attn: EIN Operation
Cincinnati, OH 45999¹⁰

This address handles applications from all 50 states. Expect your EIN by return mail in roughly four weeks, so plan ahead if you need the number to open a bank account or sign contracts.⁹

If You Don’t Have an SSN or ITIN, or Are Based Outside the U.S.

The online tool won’t work for you. If the responsible party has neither an SSN nor an ITIN and is ineligible for one, the Form SS-4 instructions allow entering “foreign” or “N/A” on that line and submitting by phone, fax, or mail. International applicants whose principal place of business is outside the United States can call (267) 941-1099, which is not toll-free, between 6:00 a.m. and 11:00 p.m. Eastern Time, Monday through Friday, or fax Form SS-4 to (304) 707-9471.⁴

You can also authorize a third-party designee, such as a California attorney or CPA, to handle the application and receive the EIN on your behalf. The designee’s authority ends as soon as the number is assigned and released, and the official EIN notice still goes to the business.⁴

Your CP 575 Confirmation Notice

After the EIN is assigned, the IRS mails a CP 575 notice to the business address on your application. That letter is your official proof of EIN assignment, and banks and lenders often ask to see it. Keep it somewhere safe.⁴ If you ever misplace both the notice and any record of the number, call the IRS Business and Specialty Tax Line at (800) 829-4933, Monday through Friday, 7:00 a.m. to 7:00 p.m. local time; after verifying your identity as an owner, officer, or partner on the account, they can give the EIN over the phone or send Letter 147C as a replacement confirmation.⁹

What’s Left to Do in California

The federal EIN is one piece of setup. California requires its own registrations depending on how your business is organized and whether you have employees.

Every LLC doing business in or organized in California owes an annual $800 franchise tax to the Franchise Tax Board. The first-year exemption that applied to LLCs formed between 2021 and 2023 has expired, so LLCs formed in 2024 or later owe the $800 in their first tax year.¹¹
If you hire employees, register with the Employment Development Department for a California payroll tax account within 15 days of paying more than $100 in wages in a calendar quarter. Registration goes through the EDD’s e-Services for Business portal.¹²
Most California cities and counties require a local business license. You get it from the city if you operate in an incorporated area, or from the county if you are in an unincorporated area.²

Your EIN itself never expires, and ordinary changes like a new business name or a move within California don’t require a new one. A new EIN is only triggered by structural changes, such as a sole proprietor incorporating, a partnership dissolving and reforming, or an LLC terminating and a new entity taking its place.¹³

1
Internal Revenue Service. Get an Employer Identification Number
2
California Office of the Small Business Advocate (CalOSBA). Setting Up Your Business in California
3
U.S. Small Business Administration. How to Build Business Credit Quickly: 5 Simple Steps
4
Internal Revenue Service. Instructions for Form SS-4 (12/2025)
5
Federal Register. Updating of Employer Identification Numbers
6
Internal Revenue Service. Certain Taxpayers May File Their Employment Taxes Annually
7
Internal Revenue Service. Responsible Parties and Nominees
8
Internal Revenue Service. About Form SS-4, Application for Employer Identification Number (EIN)
9
Internal Revenue Service. Employer Identification Number
10
Internal Revenue Service. Where to File Your Taxes for Form SS-4
11
California Franchise Tax Board. Limited Liability Company
12
California Employment Development Department. Employers: Payroll Tax Account Registration
13
Internal Revenue Service. When to Get a New EIN