EIN vs. SSN vs. ITIN: What's the Difference? | Foundery USA

An EIN, an SSN, and an ITIN are three different numbers the U.S. government uses to identify taxpayers. But they are not interchangeable. In short: an SSN identifies an individual, an EIN identifies a business, and an ITIN identifies an individual who has U.S. tax obligations but isn’t eligible for an SSN. Tax ID number or taxpayer ID, is just an umbrella term people often use for any of these three numbers.

The confusion among three is one of the most common stumbling blocks for new business owners, freelancers, and non-US residents dealing with the U.S. tax system for the first time. This guide breaks down each number clearly, shows you exactly which one you need, and covers the scenarios that trip up non-US residents specifically.

Key Takeaways

SSN identifies individuals eligible to work in the U.S.; EIN identifies businesses; ITIN identifies individuals with U.S. tax obligations who aren’t SSN-eligible.
“Tax ID,” “taxpayer ID,” and “FEIN” aren’t separate numbers, they’re informal names for one of these three.
You do not need an SSN to get an EIN. Non-US residents can apply via fax or mail using Form SS-4.
An EIN never expires; an ITIN does, if unused for five consecutive years on a federal return.
An ITIN carries zero work authorization or immigration weight, it’s a tax number only.
Non-US founders with a U.S. LLC typically only need an EIN, not a personal SSN or ITIN, unless they have an independent U.S. filing obligation.

At a Glance: EIN vs. SSN vs. ITIN

Here’s the short answer before we go deep on each one.

	SSN	EIN	ITIN
Full name	Social Security Number	Employer Identification Number	Individual Taxpayer Identification Number
Issued by	Social Security Administration (SSA)	Internal Revenue Service (IRS)	Internal Revenue Service (IRS)
Format	XXX-XX-XXXX	XX-XXXXXXX	9XX-XX-XXXX (always starts with 9)
Identifies	An individual	A business entity	An individual (non-SSN-eligible)
Who it’s for	U.S. citizens, permanent residents, certain visa holders	Any U.S. or foreign-owned business	Non-residents with U.S. tax filing obligations
Grants work authorization?	Yes	N/A (not a personal number)	No
Requires an SSN first?	N/A	No	No
Does it expire?	No	No	Yes, if unused on a federal return for 5 consecutive years
Can a non-US resident get one?	Rarely	Yes	Yes

Also known as a FEIN (Federal Employer Identification Number), the terms EIN and FEIN refer to the exact same number, just different names used interchangeably by the IRS, banks, and states. There’s no separate “FIN” or distinct FEIN system — it’s the same EIN.

One more clarification worth making early: the Social Security Administration issues SSNs, but it does not issue EINs. EINs come exclusively from the IRS. Both numbers look similar and both relate to taxes, but they come from two different federal agencies entirely.

Social Security Number (SSN)

A Social Security Number is a nine-digit number assigned to individuals (not businesses) for tracking earnings, work history, and eligibility for Social Security benefits over a person’s lifetime. An SSN always has 9 digits, formatted as XXX-XX-XXXX, split into a 3-2-4 pattern.

Who’s eligible for an SSN:

U.S. citizens
Lawful permanent residents (green card holders)
Certain nonimmigrant visa holders authorized to work in the U.S. (e.g., some H-1B or F-1 visa categories)

Most non-U.S. residents are not eligible for an SSN. This is the exact gap the ITIN was created to fill, which is why the two numbers are so often searched together.

What an SSN is used for:

Getting hired and reporting wages
Filing personal income tax returns
Applying for loans and credit
Opening personal bank accounts
Collecting Social Security and Medicare benefits
Registering to vote or obtaining a driver’s license in most states

How to get an SSN:

Complete Form SS-5 (Application for a Social Security Card) and submit it with proof of identity, age, and citizenship or immigration status at a local Social Security office. No fee is required.

An SSN functions as an individual’s default tax ID number. For most U.S. individuals filing personal taxes, your SSN is the tax identification number the IRS uses for you. It only stops being your default number if you’re a business owner who separately obtains an EIN, or a non-resident who isn’t eligible for an SSN and needs an ITIN instead.

Employer Identification Number (EIN)

An Employer Identification Number is a nine-digit number the IRS issues to identify a business entity for federal tax purposes. It functions the same way an SSN functions for an individual, except it’s tied to the business.

Format: XX-XXXXXXX: the dash placement (after two digits instead of three) is the easiest visual way to tell an EIN apart from an SSN or ITIN at a glance.

FEIN (Federal Employer Identification Number) or, in some casual references, “employer ID” or “business tax ID.” All of these terms point to the same number, there’s no meaningful difference between EIN or taxpayer identification number. An EIN is one type of taxpayer ID, specific to businesses, while taxpayer identification number is the broader term that also includes SSNs and ITINs.

Who needs an EIN:

Corporations, partnerships, and multi-member LLCs
Any business that hires employees
Nonprofits, trusts, and estates
Single-member LLCs that elect corporate tax treatment or plan to hire staff
Sole proprietors who want to separate business and personal finances (optional, but common)

What an EIN is used for

Filing business tax returns
Opening a business bank account
Applying for business loans and credit
Running payroll
Establishing business credit, separate from personal credit
Setting up retirement or pension plans as a plan administrator

How to get an EIN:

A related misconception worth clearing up is that you need an SSN to get EIN: you don’t. The IRS’s online EIN application does require a “responsible party” with a valid SSN or ITIN to complete it in one sitting, but if the responsible party has neither, they can still get an EIN by submitting Form SS-4 via fax or mail, marking “Foreign” or “N/A” where an SSN or ITIN is requested.

Individual Taxpayer Identification Number (ITIN)

An Individual Taxpayer Identification Number is a nine-digit number the IRS issues to individuals who have U.S. tax filing or reporting obligations but are not eligible for an SSN. ITIN is a tax-processing number, not a form of immigration status or work authorization. It exists purely so the IRS can track tax filings and payments from people who aren’t eligible for an SSN.

Format: 9XX-XX-XXXX: an ITIN always starts with the digit 9, which is the fastest way to visually distinguish it from an SSN.

Who typically needs an ITIN:

Nonresident aliens required to file a U.S. tax return
U.S. resident aliens who don’t qualify for an SSN
Dependents or spouses of U.S. citizens or resident aliens
Dependents or spouses of nonresident visa holders
Foreign nationals who owe U.S. tax on U.S.-sourced income (for example, a foreign owner of a U.S.-based business who doesn’t qualify for tax treaty exemptions)

What an ITIN does NOT do:

It does not authorize you to work in the United States
It does not make you eligible for Social Security benefits
It is not a substitute for a green card, visa, or any immigration document

This point is worth repeating because it’s one of the most common misconceptions. An ITIN is just a tax number, it carries no immigration or employment authority at all.

How to get an ITIN

To get an ITIN, file Form W-7 along with your federal tax return, plus documentation proving your identity and foreign status (a passport is usually sufficient on its own). You can mail this to the IRS, file it through an IRS-authorized Certifying Acceptance Agent, or bring it to a Taxpayer Assistance Center in person.

Note: If someone with an ITIN later becomes eligible for an SSN, the ITIN is retired and the IRS consolidates their tax history under the new SSN.

Which Number Do You Actually Need?

If you’re a U.S. individual or resident:

Situation	Number you need
Getting a job, filing personal taxes	SSN
Sole proprietor, no employees	SSN is sufficient (EIN optional, for privacy)
Single-member LLC, no employees	SSN or EIN (EIN recommended)
LLC with employees, or multi-member LLC	EIN required
Corporation, nonprofit, partnership	EIN required

If you’re a non-US resident:

Situation	Number you need
Foreign individual with U.S. tax filing obligations	ITIN
Foreign-owned U.S. LLC or corporation with no personal U.S. filing requirement	EIN only
Foreign freelancer or contractor invoicing a U.S. company	Usually neither — a W-8BEN form instead, though an ITIN may be requested by the payer
Non-resident selling on U.S. marketplaces (Amazon, Stripe, Etsy)	EIN, for the business entity
Foreign owner who personally owes U.S. tax on U.S.-sourced income	ITIN, in addition to the business’s EIN

SSN and ITIN identify people; EIN identifies businesses. If you’re asking “what do I, personally, need to file taxes”; you’re choosing between SSN and ITIN. If you’re asking “what does my business need”; you’re almost always looking at an EIN, regardless of your own residency status.

Common Non-Resident Scenarios

A non-US founder with a U.S. LLC generally doesn’t need an SSN or ITIN at all, the business needs an EIN, and that can be obtained without either, using Form SS-4 by fax or mail instead of the IRS’s online tool (which requires an SSN/ITIN for the responsible party). A personal ITIN only comes into play if the founder separately owes U.S. tax as an individual.

Freelancers and contractors usually sit outside this too. A foreign freelancer paid by a U.S. company typically needs neither an EIN nor an ITIN, a Form W-8BEN handles it instead. Non-residents selling through U.S. marketplaces or payment processors (Paypal, Stripe, Etsy) usually do need an EIN, since these platforms require a U.S. tax ID for payouts and 1099 reporting.

Banking is often the next step, and it’s also where an EIN alone isn’t always enough. Requirements vary by bank, and some still expect a U.S. address or in-person visit. This is the stage where non-resident founders often realize EIN formation, banking, and ongoing compliance are more interconnected than expected. Services like Foundery USA specialize in walking non-US founders through this exact process, EIN formation, U.S. LLC setup, and the follow-on banking and compliance steps.

Conclusion

An SSN, EIN, and ITIN each identifies a person, a business, and a non-SSN-eligible individual with U.S. tax obligations, respectively, and none of them substitute for one another. Knowing which one applies to your situation saves real time when opening accounts, filing returns, or setting up a business.

For non-US founders, the EIN is usually just the first step; banking, compliance, and registered agent requirements all follow from there. If you’d rather not navigate that sequence alone, Foundery USA works specifically with non-resident founders on exactly this process.

FAQs

What’s the difference between an employer ID and a tax ID?

An employer ID (EIN) is a specific type of tax ID used only for businesses. “Tax ID” is the broader, informal term that can refer to an EIN, an SSN, or an ITIN depending on who’s using it, individual or business.

Is my SSN my tax ID?

For most individuals filing personal U.S. taxes, yes — your SSN functions as your default tax ID with the IRS. It stops being the relevant number only if you separately need a business EIN or, as a non-resident ineligible for an SSN, an ITIN instead.

What is a federal employee identification number?

This is a common misphrasing of “Employer Identification Number” (EIN). Sometimes also called a Federal Employer Identification Number (FEIN). It’s the nine-digit number the IRS assigns to identify a business, not an individual employee.

Can a non-US resident get an EIN without an SSN?

Yes. Non-US residents can apply for an EIN using Form SS-4 by fax or mail, entering “Foreign” where an SSN or ITIN would normally go. The IRS’s online application does require an SSN or ITIN, so non-residents without either need to use the fax or mail route instead.

Can a foreigner open a U.S. business bank account with just an EIN?

Generally yes, alongside your business formation documents. Requirements vary by bank, and some still require an in-person visit or U.S. address, so it’s worth confirming with the specific bank or a formation service experienced with non-resident applicants before assuming any one bank will work.

Do you need an SSN to get an EIN?

No. This is one of the most misunderstood parts of the EIN application process. The IRS’s online EIN application does require a “responsible party” with a valid SSN or ITIN to complete it in one sitting — but if the responsible party doesn’t have either, they can still get an EIN by submitting Form SS-4 via fax or mail, marking “Foreign” or “N/A” where an SSN/ITIN is requested. This is the exact pathway non-U.S. residents use, and it’s covered in more detail in the non-resident section below.

Can you use an EIN instead of an SSN?

Sole proprietors and single-member LLC owners can use an EIN in place of their SSN on many business documents — vendor forms, business bank applications, and 1099 reporting — specifically to keep their personal SSN private. It doesn’t replace the SSN for personal tax filing, but it does reduce how often you need to hand out your Social Security number in a business context.

EIN vs. SSN vs. ITIN: What’s the Difference?