What Is an EIN (Employer Identification Number)?

An EIN is your business's own tax number, and you'll need it well before your first tax return. Payroll forms ask for it, and so does every business tax return. A new company can't fill in any of them until the IRS assigns the number.

EIN stands for Employer Identification Number. The IRS gives it to a business to file taxes and be identified as a taxpayer. It has nine digits written as XX-XXXXXXX, for example 12-3456789, and the IRS issues it free of charge.

How fast you get it depends on the method:

• online, if your business is in the US and you qualify: right away
• by fax: usually up to 4 business days
• by mail: about 4 weeks

People also call it an "employer ID", a "federal tax ID" or a "business tax ID", and they mean the same number. The form behind all the offline methods is Form SS-4, "Application for Employer Identification Number".

What an EIN number is for

Before you fill in another form, it helps to know what the number actually does. The IRS describes the EIN as a type of TIN (Taxpayer Identification Number). It identifies taxpayers that have to file business tax returns. You need one if you report employment or excise taxes. You also need one if you give tax statements to employees or annuitants.

According to the IRS, these taxpayers use EINs:

1. employers
2. some sole proprietors
3. corporations and partnerships
4. certain individuals
5. trusts and estates
6. other business entities

The number goes on business tax returns and payroll forms. Banks ask for it too. The fintech company Rho notes in its guide for non-US founders that most US banks need an EIN before they open a business account. That's why many owners get an EIN even when the IRS doesn't strictly require one.

When a business needs an EIN number

With so many forms and banks asking for it, you might assume every business must have one. A TurboTax guide says every commercial organization needs an EIN. But the actual rules are narrower. The SBA says a business needs one when it:

• has employees on payroll
• is set up as a corporation or a partnership
• files certain employment, excise, or alcohol, tobacco and firearms tax returns
• withholds tax on non-wage income paid to a non-resident alien
• uses a Keogh plan
• works with certain types of organizations

The SBA also suggests applying "right after you register your business". The table shows where common business types land.

If you run it as a sole proprietor

A sole proprietor is one person running a business without forming a company. If you have employees or file excise tax returns, you need an EIN. The same goes for any other item on the SBA list. If you work alone, the legal publisher Nolo says the business can keep using the owner's Social Security number. The IRS adds that a sole proprietor generally needs only one EIN, however many trade names they use.

If you formed an LLC

For an LLC, the IRS rule depends on how many owners it has and how it's taxed. A single-owner LLC with no employees and no relevant excise taxes doesn't need a separate EIN. An LLC with more than one owner needs its own EIN. And a single-member LLC that chooses to be taxed as a corporation or an S corporation needs its own EIN too.

In practice, many single-member LLC owners apply anyway. The bank will usually ask for an EIN when they open the business account.

Why your SSN can't stand in for it

If the rules say you don't need an EIN, you may wonder how it differs from your SSN. A Social Security number belongs to a person. An EIN belongs to a business or another entity, such as a trust or an estate. You can't turn one into the other or use your SSN as the company's EIN.

Some owners can use their SSN and skip the EIN:

• a sole proprietor with no employees
• a single-member LLC with no employees and no excise taxes that isn't taxed as a corporation

That changes once the business hires someone or takes on a partner. It also changes when the business becomes a corporation, and from then on it needs an EIN.

The day you apply: four ways to get an EIN

So you've decided to apply. The IRS issues EINs online, by fax and by mail, and international applicants can also apply by phone. The IRS asks you to use one method per entity. Sending the same company's form by fax and then by mail only creates confusion.

What to have on the table

For a corporation or an LLC, the IRS advises forming the company with the state first. Otherwise the EIN application may be delayed. You'll also need to name a responsible party. That's the person who owns or controls the entity and manages its funds and assets.

For a corporation this is the principal officer, and for a partnership a general partner. The responsible party has to be an individual, except for government entities. Nominees, meaning people who stand in for the real owner, can't apply and shouldn't be listed on Form SS-4.

The application also asks for:

1. the legal name
2. the address
3. the type of entity
4. the reason for applying
5. the responsible party's SSN or ITIN, if there is one

Applying online

The online application is the fastest route, but only some applicants can use it. You need all of these:

• The organization is formed in the US or a US territory and has its main place of business there.
• You're the responsible party or an authorized representative.
• You have the responsible party's SSN or ITIN.

The service doesn't run around the clock. You have to finish in one session, because progress can't be saved and the session expires after 15 minutes of inactivity. The hours are in Eastern Time:

• Monday to 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

At the end you get the confirmation notice, called CP 575. You can view it, save it and print it. Online applicants don't get it by mail, so save it before you close the page.

Applying by fax

Send Form SS-4 to 855-641-6935 if the business is in one of the 50 states or D.C. If it has no main location in a state or D.C., use 855-215-1627 from inside the US. From outside the US, use 304-707-9471. If you include your fax number, the IRS faxes the EIN back within 4 business days.

Applying by mail

Mail Form SS-4 to Internal Revenue Service, Attn: EIN Operation, Cincinnati, OH 45999. If you have no location in a state or D.C., write "Attn: EIN International Operation" instead. The city and ZIP code stay the same. Processing takes about 4 weeks, and you can check the status at 800-829-4933.

Applying by phone

The IRS no longer issues EINs by phone to domestic taxpayers. International applicants can call 267-941-1099 (not toll-free). The line is open Monday to Friday, 6:00 a.m. to 11:00 p.m. Eastern Time. You can use the EIN as soon as you get it on the call.

Letting someone receive it for you

Form SS-4 has an optional Third Party Designee section. It lets someone, such as an accountant, receive the new EIN for you. You still sign the form. The designee's authority ends once the EIN is assigned and released to them, and the IRS mails the EIN notice to you.

If you live outside the US

Now say you run the company from abroad. You can still get an EIN without an SSN, but the online application is usually closed to you. It needs both a main place of business in the US and an SSN or ITIN. Rho points out that an ITIN alone doesn't open the online tool for a business based outside the US.

That leaves three routes:

• the phone line for international applicants (267-941-1099)
• fax to 855-215-1627 or 304-707-9471
• mail to the EIN International Operation in Cincinnati

In our work with non-resident owners, we send the application by fax or with a forwarding address. The IRS letter then takes about 2 to 3 weeks on average to reach a rented virtual office in the US.

When you fill in the form, line 7b asks for the responsible party's SSN or ITIN. If they have neither and can't get one, the IRS instructions say to write "foreign" or "N/A". The line is required, so don't leave it blank.

The wider picture for foreign owners is in Can a Non-US Resident Own a US LLC? What It Involves. The ITIN is explained in What Is an ITIN? Meaning and Who Needs One. A US LLC wholly owned by a foreign person also has a yearly IRS filing, covered in Form 5472 for Foreign-Owned US LLCs: Who Must File, Due Date and Penalties.

Websites that charge a fee for a free EIN

While you search for the form, you'll likely land on sites that offer to get the EIN for a price. The number itself costs nothing. The IRS states that "You never have to pay a fee for an EIN". It also warns: "Beware of websites that charge for an EIN."

On April 1, 2025, the Federal Trade Commission published a warning about such sites. FTC staff had sent letters to businesses that file or deliver EINs. Their websites may give a false impression that they're connected to the IRS. According to the FTC, these sites don't tell visitors that the IRS tool is free. You can file complaints at ReportFraud.ftc.gov.

Paying an accountant or a formation service for their own work is an ordinary service, as long as they say clearly they aren't the IRS. The problem is a site that poses as the IRS and charges for the number.

Filing a return before the EIN arrives

With fax and mail, a few weeks can pass. Sometimes a return falls due before the EIN arrives. The Taxpayer Advocate Service says to write "Applied For" and the date you applied in the EIN space of the return. Do the same on a Form 941 deposit. Never enter your SSN or another business's EIN in that space instead.

A year later: the EIN you can't find

Once you have the EIN, keep the confirmation notice somewhere safe. But say a year has passed, a new partner asks for the number, and the notice is gone. It can still be found. The IRS suggests four places to look:

1. the original EIN confirmation notice
2. your bank or any agency where you used the number, for example for an account or a license
3. a business tax return you filed earlier, since the EIN is printed on it
4. the IRS Business and Specialty Tax Line at 800-829-4933, Monday to Friday, 7:00 a.m. to 7:00 p.m. local time

On the phone, the IRS gives the EIN only to an authorized person. That's the sole proprietor or a partner. It can also be a corporate officer, a trustee or an executor.

If you applied online and couldn't save or print the CP 575, IRS staff can send a different confirmation, Letter 147C. For problems you can't solve with the IRS directly, the Taxpayer Advocate Service is at 1-877-777-4778.

When the business changes shape

As the company grows, you may rename it or move. You may also add partners or change how it's taxed. Most of these changes don't affect the EIN, but some do. Under the general IRS rule, you need a new EIN when the ownership or structure of the entity changes. A new name or a new address doesn't require one.

A few rows need more detail. A partnership needs a new EIN when one partner takes over as a sole proprietor. It also needs one when the partnership ends and a new one starts. For a corporation, "changes entity type" means becoming a partnership or a sole proprietorship. A corporation choosing S corporation status keeps its EIN.

For an LLC, a single-member LLC needs its own EIN when it has to file excise or employment taxes. Changing the LLC's tax election to corporation or S corporation doesn't need a new one.

And if one day you close the business, the EIN doesn't get cancelled. You write to the IRS and ask it to close the business account. The number itself stays assigned to the entity.

EIN application mistakes that cost weeks

Getting an EIN is usually quick, but a few errors can slow it down. Most of them break the rules above:

• applying before the LLC or corporation is formed with the state
• naming another company or a nominee as the responsible party
• applying twice on the same day
• sending one company's form by two methods
• leaving line 7b blank for a foreign responsible party
• closing the online session without saving the CP 575

One more rule applies later. When the responsible party changes, the IRS expects Form 8822-B within 60 days. The same goes for a change of address or location.

Doing it yourself or getting help

The last choice is whether to apply yourself or get help. If you live in the US, have an SSN and are setting up an ordinary LLC, doing it yourself works well. The online application is free and takes one sitting.

Help is more useful for:

• non-US owners who have to use phone, fax or mail and want the form right the first time
• anyone forming several companies with the same responsible party, because of the one-per-day limit
• trusts, estates and LLCs choosing corporate tax status

An accountant or a formation service can act as your Third Party Designee. The EIN stays free in every case. What you pay for is the person's time. A list of what usually follows formation is in New Business Checklist: What to Do After Forming Your LLC.

While you read IRS pages, you may also see a line about reporting beneficial owners to FinCEN. Some IRS EIN pages still carry it. FinCEN removed BOI reporting for US companies and US persons, with the final rule in effect from August 14, 2026. Only companies formed under foreign law and registered to do business in a US state still report.

What to do this month

First check whether your business needs an EIN at all. If it does, apply online if you qualify. If you live abroad, use fax, mail or the phone line instead. Plan for the letter to take a few weeks.

Use only the IRS site, or a helper who says clearly they aren't the IRS. Keep the confirmation notice, since it's the easiest place to find the number later. The EIN makes the company real on paper for the IRS. Customers judge it by what they find online, and that is the part we build for new owners: a verified Google profile and listings. What usually follows formation is in New Business Checklist: What to Do After Forming Your LLC.