What Is a Tax ID Certificate and How Do You Get One?

A tax ID certificate is the IRS confirmation letter, officially called the CP 575, that proves the federal government has assigned your business an Employer Identification Number. You get one by submitting Form SS-4 through the IRS — online in minutes, by fax in about four business days, or by mail in roughly four weeks. The application is free at every stage.

What the CP 575 Actually Is

Once the IRS approves an EIN application, it generates the CP 575 automatically. The letter is printed on IRS letterhead and shows the entity’s legal name, the mailing address on file, and the assigned nine-digit EIN near the top of the page so a bank officer or state clerk can find it at a glance. It stays valid for the life of the business as long as the legal structure doesn’t change.

One detail matters more than any other: the IRS issues the CP 575 exactly once. If you lose it, no reprint is available. What you can get instead is Letter 147C, a verification letter that carries the same information and is accepted interchangeably by banks, payroll providers, and government agencies.

Do You Need One?

Not every business needs its own EIN. A sole proprietor with no employees can often file taxes under a Social Security number. The requirement kicks in once the business grows or changes form. You generally need an EIN if you:

Hire employees and have to report payroll taxes.
Operate as a partnership or corporation, regardless of whether you have employees.
Owe certain federal excise taxes.
Change your business structure, such as incorporating a sole proprietorship.
Administer an estate, trust, or retirement plan.

Plenty of sole proprietors who aren’t required to have one apply anyway, mainly to keep their Social Security number off Form W-9s handed to clients and vendors.¹

What to Have Ready Before You Apply

The application is Form SS-4, the Application for Employer Identification Number.² Whether you file online or on paper, the same information is required.

Every application names a responsible party. This is the individual who ultimately owns or controls the entity and has practical authority over its funds and assets. The responsible party has to be a real person rather than another business, and must supply a valid Social Security Number or Individual Taxpayer Identification Number. Foreign applicants who have neither can write “foreign” on that line.³

Beyond the responsible party, have the following ready:

The entity’s legal name exactly as it appears on state formation documents, plus any trade name or DBA.
The entity type — sole proprietorship, corporation, partnership, LLC, trust, or estate. LLCs also pick a tax classification (partnership, corporation, or disregarded entity).
The reason you’re applying: new business, hiring employees, opening a bank account, or another qualifying purpose.
A physical address the IRS can use to mail the CP 575.
A description of the principal business activity, which the IRS uses to code the industry.

One scheduling limit: the IRS accepts only one EIN application per responsible party per day. If you’re forming several entities at once, that constraint drives your timing.¹

How to Apply

Online

The online portal on irs.gov is the fastest route. You answer the questions, submit, and if approved the IRS issues the EIN immediately along with a confirmation letter you can print or save on the spot. The whole thing takes minutes. The trade-off is that you have to finish in one sitting: the session times out after 15 minutes of inactivity, and there’s no way to save progress or come back later to retrieve the letter.

The tool isn’t open around the clock. Its hours are Monday through Friday from 6:00 a.m. to 1:00 a.m. Eastern, Saturday from 6:00 a.m. to 9:00 p.m. Eastern, and Sunday from 6:00 p.m. to midnight Eastern. It is available only to applicants whose principal place of business is in the United States.⁴

Fax

Fax a completed Form SS-4 to 855-641-6935 (for domestic applicants) and the IRS will generally fax the EIN back within four business days. The line is open 24 hours a day, seven days a week. Include your fax number on the form so the confirmation has somewhere to go.⁵

Mail

Mailing the paper form is the slowest option. The IRS advises completing Form SS-4 four to five weeks before you need the number, and expect roughly four weeks for the CP 575 to arrive. The mailing address is Internal Revenue Service, Attn: EIN Operation, Cincinnati, OH 45999.⁵

Phone, for International Applicants Only

The IRS no longer issues EINs by phone to domestic applicants. If your principal place of business is outside the United States, you can call 267-941-1099 (not toll-free) Monday through Friday, 6:00 a.m. to 11:00 p.m. Eastern. The representative may ask you to follow up with a signed Form SS-4 by fax or mail within 24 hours.⁵

If You’ve Lost Your Certificate: Letter 147C

Because the CP 575 prints only once, misplacing it is common. The replacement is Letter 147C, an IRS verification letter confirming your existing EIN. 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 (Pacific time for callers in Alaska and Hawaii). You can ask for the letter to be faxed while you’re on the call or mailed to the address on file.⁴

Ask for the fax if you need it soon. A mailed 147C can take several weeks. Banks and government agencies treat the 147C with the same weight as the original CP 575, so nothing about the replacement is second-class.

What You’ll Use the Certificate For

The certificate comes up more often than most new owners expect, especially in the first months after formation.

Business bank accounts. Commercial banks almost always ask for a copy of the EIN confirmation letter before opening a business checking or savings account, both to confirm federal recognition of the entity and to meet anti-money-laundering verification rules. Without the letter, most banks won’t proceed.

Vendors and Form W-9. When your business is hired as a contractor or vendor, the paying company usually asks for a Form W-9 listing your name and taxpayer identification number. The EIN from your certificate goes on that line, and a correct TIN is what keeps the payer from having to apply backup withholding to your checks.⁶

Payroll. An EIN is required before a business can report and deposit employment taxes. The IRS notes that after a new EIN is issued, you may need to wait up to two weeks before making electronic tax deposits through EFTPS.⁴ If you’re onboarding employees immediately after forming the entity, plan for that gap.

State registrations. State agencies routinely ask for the federal EIN confirmation letter when you apply for a sales tax permit, professional license, or state employer tax account. A saved PDF of the CP 575 speeds those applications along.

Don’t Pay for What’s Free

A search for “apply for EIN” turns up dozens of polished sites that walk you through the same SS-4 questions and charge $50 to $200 or more for the service. Some are designed to look like official government pages, and the FTC has warned operators of these sites over implying an affiliation with the IRS that doesn’t exist. The IRS is direct about it: there is no fee for an EIN at any stage.¹

The only legitimate free application is at irs.gov. If a site asks for a credit card before it will submit your application, close the tab and go directly to the IRS.

1
Internal Revenue Service. Get an Employer Identification Number
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Internal Revenue Service. About Form SS-4, Application for Employer Identification Number (EIN)
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Internal Revenue Service. Instructions for Form SS-4 (Rev. December 2025)
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Internal Revenue Service. Employer Identification Number
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Internal Revenue Service. Instructions for Form SS-4 (12/2025)
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Internal Revenue Service. Instructions for the Requester of Form W-9