EIN vs ITIN vs SSN

Social Security Number (SSN)

What it is:

• The SSN is a nine-digit number issued by the Social Security Administration (SSA) to U.S. citizens, permanent residents, and certain work-authorized non-citizens.  

• Format is typically XXX-XX-XXXX.  

Primary uses:

• Work authorization and reporting wages.  

• Filing individual income tax returns (personal tax ID).

• Access to Social Security benefits (for eligible individuals).

• Opening many bank accounts, applying for loans, registering for certain government services.

When you need it:

• If you live in the U.S. and are eligible to work (citizen or authorized).

• If you are going to be paid wages by an employer.

• Generally, you should not get an ITIN if you’re eligible for an SSN.  

Key limitation:

• If you were eligible for an SSN, you can’t keep an ITIN; you’d switch to your SSN and notify the IRS.  

Individual Taxpayer Identification Number (ITIN)

What it is:

• The ITIN is a nine-digit number issued by the Internal Revenue Service (IRS) to individuals who cannot obtain an SSN but still have U.S. tax-filing obligations. 

• Format: begins with a “9”, e.g., 9XX-XX-XXXX.  

Primary uses:

• For individuals (resident or nonresident aliens) who need to file U.S. tax returns or claim treaty benefits but are not eligible for an SSN. 

• It does not authorize work in the U.S., nor does it provide Social Security benefits. 

When you need it:

• If you’re a non-resident alien or resident alien for tax purposes, you don’t have/work authorization for an SSN, but you must file a U.S. tax return or get a U.S. tax ID.  

Key limitation:

• Cannot be used instead of an SSN if you actually are eligible for an SSN.  

• Does not grant eligibility for many tax credits (for example, the Earned Income Tax Credit). 

Employer Identification Number (EIN)

What it is:

• The EIN is a nine-digit number issued by the IRS as a federal tax identification number for businesses, trusts, estates, and other entities.  

• Format: often XX-XXXXXXX.  

Primary uses:

• Identifying a business entity for tax filings, payroll, opening business bank accounts.  

• Required if your business has employees, operates as a corporation or partnership, files certain tax returns, or withholds taxes for non-resident aliens. 

When you need it:

• If you have a business entity distinct from a sole proprietor using their SSN, or you hire employees.

• Many businesses obtain one even if not strictly required, to separate personal and business finances.  

Key limitation:

• Cannot be used in place of an SSN or ITIN for an individual’s personal tax filing. Entities and individuals are separate.  

 Quick Comparison Table

 Why It Matters

• Using the wrong ID on tax forms or for payroll can create compliance issues or delays.  

• Keeping personal and business finances separate (e.g., using EIN for business rather than SSN) helps with privacy, accounting, and liability. 

• Non-residents, foreign nationals, and business owners must be especially careful to choose the correct ID, apply properly, and maintain compliance.