What is an EIN, and how to get one for free

An EIN, or Employer Identification Number, is a federal tax ID number the IRS gives a business. The IRS describes it as “a federal tax ID number for businesses, tax-exempt organizations and other entities”. You apply for it free, and online the IRS issues it in the same session. By fax it takes about 4 business days, and by mail about 4 weeks. A business usually needs one once it has employees, operates as a corporation or partnership, or has to file certain federal taxes.

Onlinesame session0 days

By faxabout 4 business days4 days

By mailabout 4 weeks28 days

Online, same session	0 days
By fax, about 4 business days	4 days
By mail, about 4 weeks	28 days

Online is immediate and free; fax takes about four business days and mail about four weeks.

Source: IRS, Get an EIN and Employer Identification Number pages, read November 1, 2026

What is an EIN?

An EIN is a nine-digit number the IRS uses to identify a business on its tax filings. The Form SS-4 instructions say the number is “assigned to sole proprietors, corporations, partnerships, estates, trusts, and other entities for tax filing and reporting purposes”. It identifies a business to the IRS the way a Social Security number identifies a person, and it appears on payroll filings, many business bank applications and some licenses. Some forms call it a Federal Employer Identification Number, or FEIN, which is the same number.

The number is common because new businesses are common. The US Census Bureau counts every EIN application filed for business purposes, and it counted 5,671,836 of them in 2025, up from about 2.5 million in 2005.

Do you need an EIN?

A business needs an EIN once it crosses one of a few lines the IRS draws. The IRS says you need one if you “have employees” or “will need to pay employment, excise or alcohol, tobacco, and firearms taxes”, among other conditions.

A sole proprietor with no employees often does not have to get one and can use a Social Security number instead. Many still apply, to keep that number off business paperwork. The application is free either way, so there is little cost to having one ready.

How much does an EIN cost?

Nothing. The IRS is direct about it: “You never have to pay a fee for an EIN.” The Form SS-4 instructions repeat that “you can apply for and receive an EIN free of charge on IRS.gov”.

Some websites offer to file the form for you and charge for the service. That is the same single step you can take yourself on IRS.gov in a few minutes. Paying for it buys convenience, not a different or faster number.

How do you get an EIN?

The IRS offers three routes for a US business, and a fourth for applicants based abroad.

• Online. The fastest route. The IRS says “if it’s approved, we’ll issue your EIN immediately online.” The online tool is for businesses whose principal place of business is in the US, and the IRS limits you to “only 1 EIN per responsible party per day”.
• By fax. Send Form SS-4 to the IRS fax number. With a return fax number on the form, the IRS says it “will fax a cover sheet with the EIN back to you in about 4 business days”.
• By mail. Mail Form SS-4 to the IRS. The IRS says “you’ll get your EIN in approximately 4 weeks”.
• By phone. This route is only for applicants whose principal business is outside the US.

Online is the clear choice for a US founder. It is free, it is immediate, and it uses the same Form SS-4 the other routes use.

Who is the responsible party?

Every EIN belongs to a real person who stands behind it. The IRS calls this the responsible party, “someone who owns, controls or exercises effective control over a business”. The rule is firm: “unless the applicant is a government entity, the responsible party must be an individual”, and the IRS adds that the “responsible party must be a person, not an entity”.

Two more rules catch people out. A nominee, such as a formation agent, cannot be the responsible party: the IRS says “nominees can’t apply for an EIN and shouldn’t be listed on Form SS-4”. And if the responsible party later changes, the IRS requires a business to report the change within 60 days.

The person who applies gives their own taxpayer ID, a Social Security number or an ITIN, on the form. That is why an EIN is one kind of Taxpayer Identification Number, the business kind, while an SSN is the kind issued to a person.

A note on third-party filing services

Searching for an EIN turns up sites that look official and charge a fee to file Form SS-4. The form itself is free at IRS.gov, and the IRS issues the number, not a third party. A founder who applies online gets the number in the same session at no cost. There is no faster or more official EIN than the one the IRS issues directly.

Add your company to the Index

Once a company has its EIN and is open for business, it can add itself to TheCompanyIndex for free. A person reads every entry before it goes live, and an approved entry gets its own page with a followed link. The Index never asks for an EIN or any tax number; it lists what a company does and who is behind it.

What this page could not check

• This page covers the US federal EIN only. States and cities issue their own tax IDs, which are separate from the EIN.
• This is general information, not tax or legal advice. A business with an unusual structure should read the Form SS-4 instructions or ask a tax professional.
• The online tool has limited hours and eligibility rules that the IRS can change, and the fax and mail timeframes are IRS estimates, not guarantees.
• Third-party filing fees change and vary, so none are quoted here.
• IRS pages and forms change. Each fact here is due for a check after May 1, 2027.

Sources

• Internal Revenue Service, “Employer Identification Number”, overview of what an EIN is and the application methods, last reviewed July 17, 2026.
• Internal Revenue Service, “Get an employer identification number”, the online application page, last reviewed October 16, 2026.
• Internal Revenue Service, “Responsible parties and nominees”, last reviewed August 22, 2026.
• Internal Revenue Service, “Instructions for Form SS-4”, revised December 2025.
• US Census Bureau, Business Formation Statistics, yearly sums of the monthly series, release of October 14, 2026.