How to Get a Business EIN Number: Online, Mail, Fax, or Phone

You can get a business EIN in about 15 minutes through the IRS online application, and the number is issued immediately at no cost.¹ The Employer Identification Number is a nine-digit number the IRS assigns to businesses and other entities for tax reporting, and it works like a Social Security Number for your business. You’ll need it to open a bank account, file tax returns, and run payroll.

Do You Actually Need One

Every corporation, partnership, and multi-member LLC needs an EIN, whether or not it has employees.² A single-member LLC that elects to be taxed as a corporation needs one too. Any entity that hires employees needs an EIN to report employment taxes.³ Businesses that file excise tax returns or deal in alcohol, tobacco, or firearms also need one.

A sole proprietor or single-member LLC without employees generally doesn’t need an EIN and can use the owner’s Social Security Number for tax filings. Many sole proprietors get one anyway to keep their SSN off invoices and vendor forms. A federal EIN is separate from any state-level tax ID your state may require, so check your state’s rules once you have the federal number.

What to Have Ready Before You Start

The application uses IRS Form SS-4. The online system walks through each field, but pulling this together first makes the process quick.⁴

The responsible party’s full legal name and valid SSN or ITIN. The IRS requires an individual who controls the entity’s finances and assets, meaning a principal officer, general partner, grantor, owner, or trustee.
The legal name of the entity, exactly as registered with the state. A trade name or DBA goes on a separate line.
The mailing and physical addresses, if they differ.
The entity type: corporation, partnership, LLC, estate, trust, or another structure.
The reason for applying (starting a new business, hiring employees, opening a bank account, and so on).
The month and year the business started or was acquired.
How many employees you expect in the next 12 months.

If someone else will file for you, name them as a third-party designee on Form SS-4. They can receive the EIN and answer IRS questions about the form, but their authority ends the moment the EIN is assigned, and you still have to sign the form.⁴

Applying Online

The online application is the fastest route if your responsible party has a valid SSN or ITIN and your business is located in the United States or a U.S. territory. Available hours are wider than the old business-day window:⁵

Monday through Friday, 6:00 a.m. to 1:00 a.m. (next day) Eastern Time
Saturday, 6:00 a.m. to 9:00 p.m. Eastern Time
Sunday, 6:00 p.m. to midnight Eastern Time

The system moves through entity type, reason for applying, responsible party information, and business details, validating your entries against IRS records as you go. When everything checks out, your EIN appears on the final confirmation screen.

Save or print that confirmation notice, called Notice CP 575, right then. The IRS issues it only once and will not generate a duplicate.⁶

One rule catches people off guard: you can apply for only one EIN per responsible party per day.⁵ Setting up several entities at once means spreading applications across consecutive days.

Applying by Fax, Mail, or Phone

If the online system isn’t an option, you can submit Form SS-4 by fax or by mail. Fax is much faster: the IRS typically faxes your EIN back within four business days, provided you include a return fax number on the form.² The correct fax number for your location is in the Form SS-4 instructions.

Mail is the slowest route, with processing running about four weeks. The completed form goes to Internal Revenue Service, Attn: EIN Operation, Cincinnati, OH 45999.²

International applicants whose responsible party doesn’t have an SSN or ITIN cannot use the online system. They can fax or mail Form SS-4, or call the IRS international line at 267-941-1099 (not toll-free), Monday through Friday, 6:00 a.m. to 11:00 p.m. Eastern Time. Phone is the only method where an EIN can be issued during the call.⁷ The caller has to be authorized to receive the EIN and able to answer every question on Form SS-4. A foreign address works fine; no U.S. mailing address is required.

Watch Out for Sites That Charge for This

The IRS charges no fee for an EIN. If a website asks for a credit card, you’re not on the IRS site.⁵

In April 2025, the FTC issued warnings to operators of third-party sites charging up to $300 for EIN filing services. These sites use IRS-like logos, colors, formatting, and domain names containing “IRS” or “EIN Assistant” to look official.⁸ Violations of the FTC’s Impersonation Rule can carry civil penalties of up to $53,088 per violation. The real application lives at irs.gov.

Keep the Number Somewhere You Can Find It

Store the CP 575 notice with your permanent business records. If you later misplace the number, check that notice first, then any previously filed tax returns, then the bank where you used the EIN to open an account.⁷

If none of those turn it up, 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. A representative can look up your EIN once you verify your identity.⁷ Don’t apply for a second EIN just because you lost the first one. Duplicate EINs create record-keeping problems that take real work to unwind.

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Internal Revenue Service. About Form SS-4, Application for Employer Identification Number (EIN)
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Internal Revenue Service. Employer Identification Number
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Internal Revenue Service. Instructions for Form 941
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Internal Revenue Service. Instructions for Form SS-4 – Application for Employer Identification Number
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Internal Revenue Service. Get an Employer Identification Number
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Internal Revenue Service. Notice CP 575 G – Employer Identification Number
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Taxpayer Advocate Service. Getting an EIN
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Federal Trade Commission. FTC Warns Operators of Websites that Charge for an Employer Identification Number and Claim Affiliation with the IRS